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1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 *
7 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
8 * Added handling for CPU hotplug
9 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
10 * Fix handling for CPU hotplug -- affected CPUs
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
15 *
16 */
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/notifier.h>
22#include <linux/cpufreq.h>
23#include <linux/delay.h>
24#include <linux/interrupt.h>
25#include <linux/spinlock.h>
26#include <linux/device.h>
27#include <linux/slab.h>
28#include <linux/cpu.h>
29#include <linux/completion.h>
30#include <linux/mutex.h>
31#include <linux/syscore_ops.h>
32
33#include <trace/events/power.h>
34
35/**
36 * The "cpufreq driver" - the arch- or hardware-dependent low
37 * level driver of CPUFreq support, and its spinlock. This lock
38 * also protects the cpufreq_cpu_data array.
39 */
40static struct cpufreq_driver *cpufreq_driver;
41static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
42#ifdef CONFIG_HOTPLUG_CPU
43/* This one keeps track of the previously set governor of a removed CPU */
44static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
45#endif
46static DEFINE_SPINLOCK(cpufreq_driver_lock);
47
48/*
49 * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
50 * all cpufreq/hotplug/workqueue/etc related lock issues.
51 *
52 * The rules for this semaphore:
53 * - Any routine that wants to read from the policy structure will
54 * do a down_read on this semaphore.
55 * - Any routine that will write to the policy structure and/or may take away
56 * the policy altogether (eg. CPU hotplug), will hold this lock in write
57 * mode before doing so.
58 *
59 * Additional rules:
60 * - All holders of the lock should check to make sure that the CPU they
61 * are concerned with are online after they get the lock.
62 * - Governor routines that can be called in cpufreq hotplug path should not
63 * take this sem as top level hotplug notifier handler takes this.
64 * - Lock should not be held across
65 * __cpufreq_governor(data, CPUFREQ_GOV_STOP);
66 */
67static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
68static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
69
70#define lock_policy_rwsem(mode, cpu) \
71static int lock_policy_rwsem_##mode \
72(int cpu) \
73{ \
74 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
75 BUG_ON(policy_cpu == -1); \
76 down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
77 if (unlikely(!cpu_online(cpu))) { \
78 up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
79 return -1; \
80 } \
81 \
82 return 0; \
83}
84
85lock_policy_rwsem(read, cpu);
86
87lock_policy_rwsem(write, cpu);
88
89static void unlock_policy_rwsem_read(int cpu)
90{
91 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
92 BUG_ON(policy_cpu == -1);
93 up_read(&per_cpu(cpu_policy_rwsem, policy_cpu));
94}
95
96static void unlock_policy_rwsem_write(int cpu)
97{
98 int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu);
99 BUG_ON(policy_cpu == -1);
100 up_write(&per_cpu(cpu_policy_rwsem, policy_cpu));
101}
102
103
104/* internal prototypes */
105static int __cpufreq_governor(struct cpufreq_policy *policy,
106 unsigned int event);
107static unsigned int __cpufreq_get(unsigned int cpu);
108static void handle_update(struct work_struct *work);
109
110/**
111 * Two notifier lists: the "policy" list is involved in the
112 * validation process for a new CPU frequency policy; the
113 * "transition" list for kernel code that needs to handle
114 * changes to devices when the CPU clock speed changes.
115 * The mutex locks both lists.
116 */
117static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
118static struct srcu_notifier_head cpufreq_transition_notifier_list;
119
120static bool init_cpufreq_transition_notifier_list_called;
121static int __init init_cpufreq_transition_notifier_list(void)
122{
123 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
124 init_cpufreq_transition_notifier_list_called = true;
125 return 0;
126}
127pure_initcall(init_cpufreq_transition_notifier_list);
128
129static LIST_HEAD(cpufreq_governor_list);
130static DEFINE_MUTEX(cpufreq_governor_mutex);
131
132struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
133{
134 struct cpufreq_policy *data;
135 unsigned long flags;
136
137 if (cpu >= nr_cpu_ids)
138 goto err_out;
139
140 /* get the cpufreq driver */
141 spin_lock_irqsave(&cpufreq_driver_lock, flags);
142
143 if (!cpufreq_driver)
144 goto err_out_unlock;
145
146 if (!try_module_get(cpufreq_driver->owner))
147 goto err_out_unlock;
148
149
150 /* get the CPU */
151 data = per_cpu(cpufreq_cpu_data, cpu);
152
153 if (!data)
154 goto err_out_put_module;
155
156 if (!kobject_get(&data->kobj))
157 goto err_out_put_module;
158
159 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
160 return data;
161
162err_out_put_module:
163 module_put(cpufreq_driver->owner);
164err_out_unlock:
165 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
166err_out:
167 return NULL;
168}
169EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
170
171
172void cpufreq_cpu_put(struct cpufreq_policy *data)
173{
174 kobject_put(&data->kobj);
175 module_put(cpufreq_driver->owner);
176}
177EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
178
179
180/*********************************************************************
181 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
182 *********************************************************************/
183
184/**
185 * adjust_jiffies - adjust the system "loops_per_jiffy"
186 *
187 * This function alters the system "loops_per_jiffy" for the clock
188 * speed change. Note that loops_per_jiffy cannot be updated on SMP
189 * systems as each CPU might be scaled differently. So, use the arch
190 * per-CPU loops_per_jiffy value wherever possible.
191 */
192#ifndef CONFIG_SMP
193static unsigned long l_p_j_ref;
194static unsigned int l_p_j_ref_freq;
195
196static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
197{
198 if (ci->flags & CPUFREQ_CONST_LOOPS)
199 return;
200
201 if (!l_p_j_ref_freq) {
202 l_p_j_ref = loops_per_jiffy;
203 l_p_j_ref_freq = ci->old;
204 pr_debug("saving %lu as reference value for loops_per_jiffy; "
205 "freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
206 }
207 if ((val == CPUFREQ_PRECHANGE && ci->old < ci->new) ||
208 (val == CPUFREQ_POSTCHANGE && ci->old > ci->new) ||
209 (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
210 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
211 ci->new);
212 pr_debug("scaling loops_per_jiffy to %lu "
213 "for frequency %u kHz\n", loops_per_jiffy, ci->new);
214 }
215}
216#else
217static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
218{
219 return;
220}
221#endif
222
223
224/**
225 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
226 * on frequency transition.
227 *
228 * This function calls the transition notifiers and the "adjust_jiffies"
229 * function. It is called twice on all CPU frequency changes that have
230 * external effects.
231 */
232void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state)
233{
234 struct cpufreq_policy *policy;
235
236 BUG_ON(irqs_disabled());
237
238 freqs->flags = cpufreq_driver->flags;
239 pr_debug("notification %u of frequency transition to %u kHz\n",
240 state, freqs->new);
241
242 policy = per_cpu(cpufreq_cpu_data, freqs->cpu);
243 switch (state) {
244
245 case CPUFREQ_PRECHANGE:
246 /* detect if the driver reported a value as "old frequency"
247 * which is not equal to what the cpufreq core thinks is
248 * "old frequency".
249 */
250 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
251 if ((policy) && (policy->cpu == freqs->cpu) &&
252 (policy->cur) && (policy->cur != freqs->old)) {
253 pr_debug("Warning: CPU frequency is"
254 " %u, cpufreq assumed %u kHz.\n",
255 freqs->old, policy->cur);
256 freqs->old = policy->cur;
257 }
258 }
259 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
260 CPUFREQ_PRECHANGE, freqs);
261 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
262 break;
263
264 case CPUFREQ_POSTCHANGE:
265 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
266 pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
267 (unsigned long)freqs->cpu);
268 trace_power_frequency(POWER_PSTATE, freqs->new, freqs->cpu);
269 trace_cpu_frequency(freqs->new, freqs->cpu);
270 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
271 CPUFREQ_POSTCHANGE, freqs);
272 if (likely(policy) && likely(policy->cpu == freqs->cpu))
273 policy->cur = freqs->new;
274 break;
275 }
276}
277EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
278
279
280
281/*********************************************************************
282 * SYSFS INTERFACE *
283 *********************************************************************/
284
285static struct cpufreq_governor *__find_governor(const char *str_governor)
286{
287 struct cpufreq_governor *t;
288
289 list_for_each_entry(t, &cpufreq_governor_list, governor_list)
290 if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
291 return t;
292
293 return NULL;
294}
295
296/**
297 * cpufreq_parse_governor - parse a governor string
298 */
299static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
300 struct cpufreq_governor **governor)
301{
302 int err = -EINVAL;
303
304 if (!cpufreq_driver)
305 goto out;
306
307 if (cpufreq_driver->setpolicy) {
308 if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
309 *policy = CPUFREQ_POLICY_PERFORMANCE;
310 err = 0;
311 } else if (!strnicmp(str_governor, "powersave",
312 CPUFREQ_NAME_LEN)) {
313 *policy = CPUFREQ_POLICY_POWERSAVE;
314 err = 0;
315 }
316 } else if (cpufreq_driver->target) {
317 struct cpufreq_governor *t;
318
319 mutex_lock(&cpufreq_governor_mutex);
320
321 t = __find_governor(str_governor);
322
323 if (t == NULL) {
324 int ret;
325
326 mutex_unlock(&cpufreq_governor_mutex);
327 ret = request_module("cpufreq_%s", str_governor);
328 mutex_lock(&cpufreq_governor_mutex);
329
330 if (ret == 0)
331 t = __find_governor(str_governor);
332 }
333
334 if (t != NULL) {
335 *governor = t;
336 err = 0;
337 }
338
339 mutex_unlock(&cpufreq_governor_mutex);
340 }
341out:
342 return err;
343}
344
345
346/**
347 * cpufreq_per_cpu_attr_read() / show_##file_name() -
348 * print out cpufreq information
349 *
350 * Write out information from cpufreq_driver->policy[cpu]; object must be
351 * "unsigned int".
352 */
353
354#define show_one(file_name, object) \
355static ssize_t show_##file_name \
356(struct cpufreq_policy *policy, char *buf) \
357{ \
358 return sprintf(buf, "%u\n", policy->object); \
359}
360
361show_one(cpuinfo_min_freq, cpuinfo.min_freq);
362show_one(cpuinfo_max_freq, cpuinfo.max_freq);
363show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
364show_one(scaling_min_freq, min);
365show_one(scaling_max_freq, max);
366show_one(scaling_cur_freq, cur);
367
368static int __cpufreq_set_policy(struct cpufreq_policy *data,
369 struct cpufreq_policy *policy);
370
371/**
372 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
373 */
374#define store_one(file_name, object) \
375static ssize_t store_##file_name \
376(struct cpufreq_policy *policy, const char *buf, size_t count) \
377{ \
378 unsigned int ret = -EINVAL; \
379 struct cpufreq_policy new_policy; \
380 \
381 ret = cpufreq_get_policy(&new_policy, policy->cpu); \
382 if (ret) \
383 return -EINVAL; \
384 \
385 ret = sscanf(buf, "%u", &new_policy.object); \
386 if (ret != 1) \
387 return -EINVAL; \
388 \
389 ret = __cpufreq_set_policy(policy, &new_policy); \
390 policy->user_policy.object = policy->object; \
391 \
392 return ret ? ret : count; \
393}
394
395store_one(scaling_min_freq, min);
396store_one(scaling_max_freq, max);
397
398/**
399 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
400 */
401static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
402 char *buf)
403{
404 unsigned int cur_freq = __cpufreq_get(policy->cpu);
405 if (!cur_freq)
406 return sprintf(buf, "<unknown>");
407 return sprintf(buf, "%u\n", cur_freq);
408}
409
410
411/**
412 * show_scaling_governor - show the current policy for the specified CPU
413 */
414static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
415{
416 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
417 return sprintf(buf, "powersave\n");
418 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
419 return sprintf(buf, "performance\n");
420 else if (policy->governor)
421 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
422 policy->governor->name);
423 return -EINVAL;
424}
425
426
427/**
428 * store_scaling_governor - store policy for the specified CPU
429 */
430static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
431 const char *buf, size_t count)
432{
433 unsigned int ret = -EINVAL;
434 char str_governor[16];
435 struct cpufreq_policy new_policy;
436
437 ret = cpufreq_get_policy(&new_policy, policy->cpu);
438 if (ret)
439 return ret;
440
441 ret = sscanf(buf, "%15s", str_governor);
442 if (ret != 1)
443 return -EINVAL;
444
445 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
446 &new_policy.governor))
447 return -EINVAL;
448
449 /* Do not use cpufreq_set_policy here or the user_policy.max
450 will be wrongly overridden */
451 ret = __cpufreq_set_policy(policy, &new_policy);
452
453 policy->user_policy.policy = policy->policy;
454 policy->user_policy.governor = policy->governor;
455
456 if (ret)
457 return ret;
458 else
459 return count;
460}
461
462/**
463 * show_scaling_driver - show the cpufreq driver currently loaded
464 */
465static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
466{
467 return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
468}
469
470/**
471 * show_scaling_available_governors - show the available CPUfreq governors
472 */
473static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
474 char *buf)
475{
476 ssize_t i = 0;
477 struct cpufreq_governor *t;
478
479 if (!cpufreq_driver->target) {
480 i += sprintf(buf, "performance powersave");
481 goto out;
482 }
483
484 list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
485 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
486 - (CPUFREQ_NAME_LEN + 2)))
487 goto out;
488 i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
489 }
490out:
491 i += sprintf(&buf[i], "\n");
492 return i;
493}
494
495static ssize_t show_cpus(const struct cpumask *mask, char *buf)
496{
497 ssize_t i = 0;
498 unsigned int cpu;
499
500 for_each_cpu(cpu, mask) {
501 if (i)
502 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
503 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
504 if (i >= (PAGE_SIZE - 5))
505 break;
506 }
507 i += sprintf(&buf[i], "\n");
508 return i;
509}
510
511/**
512 * show_related_cpus - show the CPUs affected by each transition even if
513 * hw coordination is in use
514 */
515static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
516{
517 if (cpumask_empty(policy->related_cpus))
518 return show_cpus(policy->cpus, buf);
519 return show_cpus(policy->related_cpus, buf);
520}
521
522/**
523 * show_affected_cpus - show the CPUs affected by each transition
524 */
525static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
526{
527 return show_cpus(policy->cpus, buf);
528}
529
530static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
531 const char *buf, size_t count)
532{
533 unsigned int freq = 0;
534 unsigned int ret;
535
536 if (!policy->governor || !policy->governor->store_setspeed)
537 return -EINVAL;
538
539 ret = sscanf(buf, "%u", &freq);
540 if (ret != 1)
541 return -EINVAL;
542
543 policy->governor->store_setspeed(policy, freq);
544
545 return count;
546}
547
548static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
549{
550 if (!policy->governor || !policy->governor->show_setspeed)
551 return sprintf(buf, "<unsupported>\n");
552
553 return policy->governor->show_setspeed(policy, buf);
554}
555
556/**
557 * show_scaling_driver - show the current cpufreq HW/BIOS limitation
558 */
559static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
560{
561 unsigned int limit;
562 int ret;
563 if (cpufreq_driver->bios_limit) {
564 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
565 if (!ret)
566 return sprintf(buf, "%u\n", limit);
567 }
568 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
569}
570
571cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
572cpufreq_freq_attr_ro(cpuinfo_min_freq);
573cpufreq_freq_attr_ro(cpuinfo_max_freq);
574cpufreq_freq_attr_ro(cpuinfo_transition_latency);
575cpufreq_freq_attr_ro(scaling_available_governors);
576cpufreq_freq_attr_ro(scaling_driver);
577cpufreq_freq_attr_ro(scaling_cur_freq);
578cpufreq_freq_attr_ro(bios_limit);
579cpufreq_freq_attr_ro(related_cpus);
580cpufreq_freq_attr_ro(affected_cpus);
581cpufreq_freq_attr_rw(scaling_min_freq);
582cpufreq_freq_attr_rw(scaling_max_freq);
583cpufreq_freq_attr_rw(scaling_governor);
584cpufreq_freq_attr_rw(scaling_setspeed);
585
586static struct attribute *default_attrs[] = {
587 &cpuinfo_min_freq.attr,
588 &cpuinfo_max_freq.attr,
589 &cpuinfo_transition_latency.attr,
590 &scaling_min_freq.attr,
591 &scaling_max_freq.attr,
592 &affected_cpus.attr,
593 &related_cpus.attr,
594 &scaling_governor.attr,
595 &scaling_driver.attr,
596 &scaling_available_governors.attr,
597 &scaling_setspeed.attr,
598 NULL
599};
600
601struct kobject *cpufreq_global_kobject;
602EXPORT_SYMBOL(cpufreq_global_kobject);
603
604#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
605#define to_attr(a) container_of(a, struct freq_attr, attr)
606
607static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
608{
609 struct cpufreq_policy *policy = to_policy(kobj);
610 struct freq_attr *fattr = to_attr(attr);
611 ssize_t ret = -EINVAL;
612 policy = cpufreq_cpu_get(policy->cpu);
613 if (!policy)
614 goto no_policy;
615
616 if (lock_policy_rwsem_read(policy->cpu) < 0)
617 goto fail;
618
619 if (fattr->show)
620 ret = fattr->show(policy, buf);
621 else
622 ret = -EIO;
623
624 unlock_policy_rwsem_read(policy->cpu);
625fail:
626 cpufreq_cpu_put(policy);
627no_policy:
628 return ret;
629}
630
631static ssize_t store(struct kobject *kobj, struct attribute *attr,
632 const char *buf, size_t count)
633{
634 struct cpufreq_policy *policy = to_policy(kobj);
635 struct freq_attr *fattr = to_attr(attr);
636 ssize_t ret = -EINVAL;
637 policy = cpufreq_cpu_get(policy->cpu);
638 if (!policy)
639 goto no_policy;
640
641 if (lock_policy_rwsem_write(policy->cpu) < 0)
642 goto fail;
643
644 if (fattr->store)
645 ret = fattr->store(policy, buf, count);
646 else
647 ret = -EIO;
648
649 unlock_policy_rwsem_write(policy->cpu);
650fail:
651 cpufreq_cpu_put(policy);
652no_policy:
653 return ret;
654}
655
656static void cpufreq_sysfs_release(struct kobject *kobj)
657{
658 struct cpufreq_policy *policy = to_policy(kobj);
659 pr_debug("last reference is dropped\n");
660 complete(&policy->kobj_unregister);
661}
662
663static const struct sysfs_ops sysfs_ops = {
664 .show = show,
665 .store = store,
666};
667
668static struct kobj_type ktype_cpufreq = {
669 .sysfs_ops = &sysfs_ops,
670 .default_attrs = default_attrs,
671 .release = cpufreq_sysfs_release,
672};
673
674/*
675 * Returns:
676 * Negative: Failure
677 * 0: Success
678 * Positive: When we have a managed CPU and the sysfs got symlinked
679 */
680static int cpufreq_add_dev_policy(unsigned int cpu,
681 struct cpufreq_policy *policy,
682 struct sys_device *sys_dev)
683{
684 int ret = 0;
685#ifdef CONFIG_SMP
686 unsigned long flags;
687 unsigned int j;
688#ifdef CONFIG_HOTPLUG_CPU
689 struct cpufreq_governor *gov;
690
691 gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
692 if (gov) {
693 policy->governor = gov;
694 pr_debug("Restoring governor %s for cpu %d\n",
695 policy->governor->name, cpu);
696 }
697#endif
698
699 for_each_cpu(j, policy->cpus) {
700 struct cpufreq_policy *managed_policy;
701
702 if (cpu == j)
703 continue;
704
705 /* Check for existing affected CPUs.
706 * They may not be aware of it due to CPU Hotplug.
707 * cpufreq_cpu_put is called when the device is removed
708 * in __cpufreq_remove_dev()
709 */
710 managed_policy = cpufreq_cpu_get(j);
711 if (unlikely(managed_policy)) {
712
713 /* Set proper policy_cpu */
714 unlock_policy_rwsem_write(cpu);
715 per_cpu(cpufreq_policy_cpu, cpu) = managed_policy->cpu;
716
717 if (lock_policy_rwsem_write(cpu) < 0) {
718 /* Should not go through policy unlock path */
719 if (cpufreq_driver->exit)
720 cpufreq_driver->exit(policy);
721 cpufreq_cpu_put(managed_policy);
722 return -EBUSY;
723 }
724
725 spin_lock_irqsave(&cpufreq_driver_lock, flags);
726 cpumask_copy(managed_policy->cpus, policy->cpus);
727 per_cpu(cpufreq_cpu_data, cpu) = managed_policy;
728 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
729
730 pr_debug("CPU already managed, adding link\n");
731 ret = sysfs_create_link(&sys_dev->kobj,
732 &managed_policy->kobj,
733 "cpufreq");
734 if (ret)
735 cpufreq_cpu_put(managed_policy);
736 /*
737 * Success. We only needed to be added to the mask.
738 * Call driver->exit() because only the cpu parent of
739 * the kobj needed to call init().
740 */
741 if (cpufreq_driver->exit)
742 cpufreq_driver->exit(policy);
743
744 if (!ret)
745 return 1;
746 else
747 return ret;
748 }
749 }
750#endif
751 return ret;
752}
753
754
755/* symlink affected CPUs */
756static int cpufreq_add_dev_symlink(unsigned int cpu,
757 struct cpufreq_policy *policy)
758{
759 unsigned int j;
760 int ret = 0;
761
762 for_each_cpu(j, policy->cpus) {
763 struct cpufreq_policy *managed_policy;
764 struct sys_device *cpu_sys_dev;
765
766 if (j == cpu)
767 continue;
768 if (!cpu_online(j))
769 continue;
770
771 pr_debug("CPU %u already managed, adding link\n", j);
772 managed_policy = cpufreq_cpu_get(cpu);
773 cpu_sys_dev = get_cpu_sysdev(j);
774 ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
775 "cpufreq");
776 if (ret) {
777 cpufreq_cpu_put(managed_policy);
778 return ret;
779 }
780 }
781 return ret;
782}
783
784static int cpufreq_add_dev_interface(unsigned int cpu,
785 struct cpufreq_policy *policy,
786 struct sys_device *sys_dev)
787{
788 struct cpufreq_policy new_policy;
789 struct freq_attr **drv_attr;
790 unsigned long flags;
791 int ret = 0;
792 unsigned int j;
793
794 /* prepare interface data */
795 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
796 &sys_dev->kobj, "cpufreq");
797 if (ret)
798 return ret;
799
800 /* set up files for this cpu device */
801 drv_attr = cpufreq_driver->attr;
802 while ((drv_attr) && (*drv_attr)) {
803 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
804 if (ret)
805 goto err_out_kobj_put;
806 drv_attr++;
807 }
808 if (cpufreq_driver->get) {
809 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
810 if (ret)
811 goto err_out_kobj_put;
812 }
813 if (cpufreq_driver->target) {
814 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
815 if (ret)
816 goto err_out_kobj_put;
817 }
818 if (cpufreq_driver->bios_limit) {
819 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
820 if (ret)
821 goto err_out_kobj_put;
822 }
823
824 spin_lock_irqsave(&cpufreq_driver_lock, flags);
825 for_each_cpu(j, policy->cpus) {
826 if (!cpu_online(j))
827 continue;
828 per_cpu(cpufreq_cpu_data, j) = policy;
829 per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
830 }
831 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
832
833 ret = cpufreq_add_dev_symlink(cpu, policy);
834 if (ret)
835 goto err_out_kobj_put;
836
837 memcpy(&new_policy, policy, sizeof(struct cpufreq_policy));
838 /* assure that the starting sequence is run in __cpufreq_set_policy */
839 policy->governor = NULL;
840
841 /* set default policy */
842 ret = __cpufreq_set_policy(policy, &new_policy);
843 policy->user_policy.policy = policy->policy;
844 policy->user_policy.governor = policy->governor;
845
846 if (ret) {
847 pr_debug("setting policy failed\n");
848 if (cpufreq_driver->exit)
849 cpufreq_driver->exit(policy);
850 }
851 return ret;
852
853err_out_kobj_put:
854 kobject_put(&policy->kobj);
855 wait_for_completion(&policy->kobj_unregister);
856 return ret;
857}
858
859
860/**
861 * cpufreq_add_dev - add a CPU device
862 *
863 * Adds the cpufreq interface for a CPU device.
864 *
865 * The Oracle says: try running cpufreq registration/unregistration concurrently
866 * with with cpu hotplugging and all hell will break loose. Tried to clean this
867 * mess up, but more thorough testing is needed. - Mathieu
868 */
869static int cpufreq_add_dev(struct sys_device *sys_dev)
870{
871 unsigned int cpu = sys_dev->id;
872 int ret = 0, found = 0;
873 struct cpufreq_policy *policy;
874 unsigned long flags;
875 unsigned int j;
876#ifdef CONFIG_HOTPLUG_CPU
877 int sibling;
878#endif
879
880 if (cpu_is_offline(cpu))
881 return 0;
882
883 pr_debug("adding CPU %u\n", cpu);
884
885#ifdef CONFIG_SMP
886 /* check whether a different CPU already registered this
887 * CPU because it is in the same boat. */
888 policy = cpufreq_cpu_get(cpu);
889 if (unlikely(policy)) {
890 cpufreq_cpu_put(policy);
891 return 0;
892 }
893#endif
894
895 if (!try_module_get(cpufreq_driver->owner)) {
896 ret = -EINVAL;
897 goto module_out;
898 }
899
900 ret = -ENOMEM;
901 policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL);
902 if (!policy)
903 goto nomem_out;
904
905 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
906 goto err_free_policy;
907
908 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
909 goto err_free_cpumask;
910
911 policy->cpu = cpu;
912 cpumask_copy(policy->cpus, cpumask_of(cpu));
913
914 /* Initially set CPU itself as the policy_cpu */
915 per_cpu(cpufreq_policy_cpu, cpu) = cpu;
916 ret = (lock_policy_rwsem_write(cpu) < 0);
917 WARN_ON(ret);
918
919 init_completion(&policy->kobj_unregister);
920 INIT_WORK(&policy->update, handle_update);
921
922 /* Set governor before ->init, so that driver could check it */
923#ifdef CONFIG_HOTPLUG_CPU
924 for_each_online_cpu(sibling) {
925 struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling);
926 if (cp && cp->governor &&
927 (cpumask_test_cpu(cpu, cp->related_cpus))) {
928 policy->governor = cp->governor;
929 found = 1;
930 break;
931 }
932 }
933#endif
934 if (!found)
935 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
936 /* call driver. From then on the cpufreq must be able
937 * to accept all calls to ->verify and ->setpolicy for this CPU
938 */
939 ret = cpufreq_driver->init(policy);
940 if (ret) {
941 pr_debug("initialization failed\n");
942 goto err_unlock_policy;
943 }
944 policy->user_policy.min = policy->min;
945 policy->user_policy.max = policy->max;
946
947 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
948 CPUFREQ_START, policy);
949
950 ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
951 if (ret) {
952 if (ret > 0)
953 /* This is a managed cpu, symlink created,
954 exit with 0 */
955 ret = 0;
956 goto err_unlock_policy;
957 }
958
959 ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
960 if (ret)
961 goto err_out_unregister;
962
963 unlock_policy_rwsem_write(cpu);
964
965 kobject_uevent(&policy->kobj, KOBJ_ADD);
966 module_put(cpufreq_driver->owner);
967 pr_debug("initialization complete\n");
968
969 return 0;
970
971
972err_out_unregister:
973 spin_lock_irqsave(&cpufreq_driver_lock, flags);
974 for_each_cpu(j, policy->cpus)
975 per_cpu(cpufreq_cpu_data, j) = NULL;
976 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
977
978 kobject_put(&policy->kobj);
979 wait_for_completion(&policy->kobj_unregister);
980
981err_unlock_policy:
982 unlock_policy_rwsem_write(cpu);
983 free_cpumask_var(policy->related_cpus);
984err_free_cpumask:
985 free_cpumask_var(policy->cpus);
986err_free_policy:
987 kfree(policy);
988nomem_out:
989 module_put(cpufreq_driver->owner);
990module_out:
991 return ret;
992}
993
994
995/**
996 * __cpufreq_remove_dev - remove a CPU device
997 *
998 * Removes the cpufreq interface for a CPU device.
999 * Caller should already have policy_rwsem in write mode for this CPU.
1000 * This routine frees the rwsem before returning.
1001 */
1002static int __cpufreq_remove_dev(struct sys_device *sys_dev)
1003{
1004 unsigned int cpu = sys_dev->id;
1005 unsigned long flags;
1006 struct cpufreq_policy *data;
1007 struct kobject *kobj;
1008 struct completion *cmp;
1009#ifdef CONFIG_SMP
1010 struct sys_device *cpu_sys_dev;
1011 unsigned int j;
1012#endif
1013
1014 pr_debug("unregistering CPU %u\n", cpu);
1015
1016 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1017 data = per_cpu(cpufreq_cpu_data, cpu);
1018
1019 if (!data) {
1020 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1021 unlock_policy_rwsem_write(cpu);
1022 return -EINVAL;
1023 }
1024 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1025
1026
1027#ifdef CONFIG_SMP
1028 /* if this isn't the CPU which is the parent of the kobj, we
1029 * only need to unlink, put and exit
1030 */
1031 if (unlikely(cpu != data->cpu)) {
1032 pr_debug("removing link\n");
1033 cpumask_clear_cpu(cpu, data->cpus);
1034 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1035 kobj = &sys_dev->kobj;
1036 cpufreq_cpu_put(data);
1037 unlock_policy_rwsem_write(cpu);
1038 sysfs_remove_link(kobj, "cpufreq");
1039 return 0;
1040 }
1041#endif
1042
1043#ifdef CONFIG_SMP
1044
1045#ifdef CONFIG_HOTPLUG_CPU
1046 strncpy(per_cpu(cpufreq_cpu_governor, cpu), data->governor->name,
1047 CPUFREQ_NAME_LEN);
1048#endif
1049
1050 /* if we have other CPUs still registered, we need to unlink them,
1051 * or else wait_for_completion below will lock up. Clean the
1052 * per_cpu(cpufreq_cpu_data) while holding the lock, and remove
1053 * the sysfs links afterwards.
1054 */
1055 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1056 for_each_cpu(j, data->cpus) {
1057 if (j == cpu)
1058 continue;
1059 per_cpu(cpufreq_cpu_data, j) = NULL;
1060 }
1061 }
1062
1063 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1064
1065 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1066 for_each_cpu(j, data->cpus) {
1067 if (j == cpu)
1068 continue;
1069 pr_debug("removing link for cpu %u\n", j);
1070#ifdef CONFIG_HOTPLUG_CPU
1071 strncpy(per_cpu(cpufreq_cpu_governor, j),
1072 data->governor->name, CPUFREQ_NAME_LEN);
1073#endif
1074 cpu_sys_dev = get_cpu_sysdev(j);
1075 kobj = &cpu_sys_dev->kobj;
1076 unlock_policy_rwsem_write(cpu);
1077 sysfs_remove_link(kobj, "cpufreq");
1078 lock_policy_rwsem_write(cpu);
1079 cpufreq_cpu_put(data);
1080 }
1081 }
1082#else
1083 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1084#endif
1085
1086 if (cpufreq_driver->target)
1087 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1088
1089 kobj = &data->kobj;
1090 cmp = &data->kobj_unregister;
1091 unlock_policy_rwsem_write(cpu);
1092 kobject_put(kobj);
1093
1094 /* we need to make sure that the underlying kobj is actually
1095 * not referenced anymore by anybody before we proceed with
1096 * unloading.
1097 */
1098 pr_debug("waiting for dropping of refcount\n");
1099 wait_for_completion(cmp);
1100 pr_debug("wait complete\n");
1101
1102 lock_policy_rwsem_write(cpu);
1103 if (cpufreq_driver->exit)
1104 cpufreq_driver->exit(data);
1105 unlock_policy_rwsem_write(cpu);
1106
1107#ifdef CONFIG_HOTPLUG_CPU
1108 /* when the CPU which is the parent of the kobj is hotplugged
1109 * offline, check for siblings, and create cpufreq sysfs interface
1110 * and symlinks
1111 */
1112 if (unlikely(cpumask_weight(data->cpus) > 1)) {
1113 /* first sibling now owns the new sysfs dir */
1114 cpumask_clear_cpu(cpu, data->cpus);
1115 cpufreq_add_dev(get_cpu_sysdev(cpumask_first(data->cpus)));
1116
1117 /* finally remove our own symlink */
1118 lock_policy_rwsem_write(cpu);
1119 __cpufreq_remove_dev(sys_dev);
1120 }
1121#endif
1122
1123 free_cpumask_var(data->related_cpus);
1124 free_cpumask_var(data->cpus);
1125 kfree(data);
1126
1127 return 0;
1128}
1129
1130
1131static int cpufreq_remove_dev(struct sys_device *sys_dev)
1132{
1133 unsigned int cpu = sys_dev->id;
1134 int retval;
1135
1136 if (cpu_is_offline(cpu))
1137 return 0;
1138
1139 if (unlikely(lock_policy_rwsem_write(cpu)))
1140 BUG();
1141
1142 retval = __cpufreq_remove_dev(sys_dev);
1143 return retval;
1144}
1145
1146
1147static void handle_update(struct work_struct *work)
1148{
1149 struct cpufreq_policy *policy =
1150 container_of(work, struct cpufreq_policy, update);
1151 unsigned int cpu = policy->cpu;
1152 pr_debug("handle_update for cpu %u called\n", cpu);
1153 cpufreq_update_policy(cpu);
1154}
1155
1156/**
1157 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're in deep trouble.
1158 * @cpu: cpu number
1159 * @old_freq: CPU frequency the kernel thinks the CPU runs at
1160 * @new_freq: CPU frequency the CPU actually runs at
1161 *
1162 * We adjust to current frequency first, and need to clean up later.
1163 * So either call to cpufreq_update_policy() or schedule handle_update()).
1164 */
1165static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
1166 unsigned int new_freq)
1167{
1168 struct cpufreq_freqs freqs;
1169
1170 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
1171 "core thinks of %u, is %u kHz.\n", old_freq, new_freq);
1172
1173 freqs.cpu = cpu;
1174 freqs.old = old_freq;
1175 freqs.new = new_freq;
1176 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
1177 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
1178}
1179
1180
1181/**
1182 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1183 * @cpu: CPU number
1184 *
1185 * This is the last known freq, without actually getting it from the driver.
1186 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1187 */
1188unsigned int cpufreq_quick_get(unsigned int cpu)
1189{
1190 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1191 unsigned int ret_freq = 0;
1192
1193 if (policy) {
1194 ret_freq = policy->cur;
1195 cpufreq_cpu_put(policy);
1196 }
1197
1198 return ret_freq;
1199}
1200EXPORT_SYMBOL(cpufreq_quick_get);
1201
1202/**
1203 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1204 * @cpu: CPU number
1205 *
1206 * Just return the max possible frequency for a given CPU.
1207 */
1208unsigned int cpufreq_quick_get_max(unsigned int cpu)
1209{
1210 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1211 unsigned int ret_freq = 0;
1212
1213 if (policy) {
1214 ret_freq = policy->max;
1215 cpufreq_cpu_put(policy);
1216 }
1217
1218 return ret_freq;
1219}
1220EXPORT_SYMBOL(cpufreq_quick_get_max);
1221
1222
1223static unsigned int __cpufreq_get(unsigned int cpu)
1224{
1225 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1226 unsigned int ret_freq = 0;
1227
1228 if (!cpufreq_driver->get)
1229 return ret_freq;
1230
1231 ret_freq = cpufreq_driver->get(cpu);
1232
1233 if (ret_freq && policy->cur &&
1234 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1235 /* verify no discrepancy between actual and
1236 saved value exists */
1237 if (unlikely(ret_freq != policy->cur)) {
1238 cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
1239 schedule_work(&policy->update);
1240 }
1241 }
1242
1243 return ret_freq;
1244}
1245
1246/**
1247 * cpufreq_get - get the current CPU frequency (in kHz)
1248 * @cpu: CPU number
1249 *
1250 * Get the CPU current (static) CPU frequency
1251 */
1252unsigned int cpufreq_get(unsigned int cpu)
1253{
1254 unsigned int ret_freq = 0;
1255 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1256
1257 if (!policy)
1258 goto out;
1259
1260 if (unlikely(lock_policy_rwsem_read(cpu)))
1261 goto out_policy;
1262
1263 ret_freq = __cpufreq_get(cpu);
1264
1265 unlock_policy_rwsem_read(cpu);
1266
1267out_policy:
1268 cpufreq_cpu_put(policy);
1269out:
1270 return ret_freq;
1271}
1272EXPORT_SYMBOL(cpufreq_get);
1273
1274static struct sysdev_driver cpufreq_sysdev_driver = {
1275 .add = cpufreq_add_dev,
1276 .remove = cpufreq_remove_dev,
1277};
1278
1279
1280/**
1281 * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
1282 *
1283 * This function is only executed for the boot processor. The other CPUs
1284 * have been put offline by means of CPU hotplug.
1285 */
1286static int cpufreq_bp_suspend(void)
1287{
1288 int ret = 0;
1289
1290 int cpu = smp_processor_id();
1291 struct cpufreq_policy *cpu_policy;
1292
1293 pr_debug("suspending cpu %u\n", cpu);
1294
1295 /* If there's no policy for the boot CPU, we have nothing to do. */
1296 cpu_policy = cpufreq_cpu_get(cpu);
1297 if (!cpu_policy)
1298 return 0;
1299
1300 if (cpufreq_driver->suspend) {
1301 ret = cpufreq_driver->suspend(cpu_policy);
1302 if (ret)
1303 printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
1304 "step on CPU %u\n", cpu_policy->cpu);
1305 }
1306
1307 cpufreq_cpu_put(cpu_policy);
1308 return ret;
1309}
1310
1311/**
1312 * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
1313 *
1314 * 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
1315 * 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
1316 * restored. It will verify that the current freq is in sync with
1317 * what we believe it to be. This is a bit later than when it
1318 * should be, but nonethteless it's better than calling
1319 * cpufreq_driver->get() here which might re-enable interrupts...
1320 *
1321 * This function is only executed for the boot CPU. The other CPUs have not
1322 * been turned on yet.
1323 */
1324static void cpufreq_bp_resume(void)
1325{
1326 int ret = 0;
1327
1328 int cpu = smp_processor_id();
1329 struct cpufreq_policy *cpu_policy;
1330
1331 pr_debug("resuming cpu %u\n", cpu);
1332
1333 /* If there's no policy for the boot CPU, we have nothing to do. */
1334 cpu_policy = cpufreq_cpu_get(cpu);
1335 if (!cpu_policy)
1336 return;
1337
1338 if (cpufreq_driver->resume) {
1339 ret = cpufreq_driver->resume(cpu_policy);
1340 if (ret) {
1341 printk(KERN_ERR "cpufreq: resume failed in ->resume "
1342 "step on CPU %u\n", cpu_policy->cpu);
1343 goto fail;
1344 }
1345 }
1346
1347 schedule_work(&cpu_policy->update);
1348
1349fail:
1350 cpufreq_cpu_put(cpu_policy);
1351}
1352
1353static struct syscore_ops cpufreq_syscore_ops = {
1354 .suspend = cpufreq_bp_suspend,
1355 .resume = cpufreq_bp_resume,
1356};
1357
1358
1359/*********************************************************************
1360 * NOTIFIER LISTS INTERFACE *
1361 *********************************************************************/
1362
1363/**
1364 * cpufreq_register_notifier - register a driver with cpufreq
1365 * @nb: notifier function to register
1366 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1367 *
1368 * Add a driver to one of two lists: either a list of drivers that
1369 * are notified about clock rate changes (once before and once after
1370 * the transition), or a list of drivers that are notified about
1371 * changes in cpufreq policy.
1372 *
1373 * This function may sleep, and has the same return conditions as
1374 * blocking_notifier_chain_register.
1375 */
1376int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1377{
1378 int ret;
1379
1380 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1381
1382 switch (list) {
1383 case CPUFREQ_TRANSITION_NOTIFIER:
1384 ret = srcu_notifier_chain_register(
1385 &cpufreq_transition_notifier_list, nb);
1386 break;
1387 case CPUFREQ_POLICY_NOTIFIER:
1388 ret = blocking_notifier_chain_register(
1389 &cpufreq_policy_notifier_list, nb);
1390 break;
1391 default:
1392 ret = -EINVAL;
1393 }
1394
1395 return ret;
1396}
1397EXPORT_SYMBOL(cpufreq_register_notifier);
1398
1399
1400/**
1401 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1402 * @nb: notifier block to be unregistered
1403 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1404 *
1405 * Remove a driver from the CPU frequency notifier list.
1406 *
1407 * This function may sleep, and has the same return conditions as
1408 * blocking_notifier_chain_unregister.
1409 */
1410int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1411{
1412 int ret;
1413
1414 switch (list) {
1415 case CPUFREQ_TRANSITION_NOTIFIER:
1416 ret = srcu_notifier_chain_unregister(
1417 &cpufreq_transition_notifier_list, nb);
1418 break;
1419 case CPUFREQ_POLICY_NOTIFIER:
1420 ret = blocking_notifier_chain_unregister(
1421 &cpufreq_policy_notifier_list, nb);
1422 break;
1423 default:
1424 ret = -EINVAL;
1425 }
1426
1427 return ret;
1428}
1429EXPORT_SYMBOL(cpufreq_unregister_notifier);
1430
1431
1432/*********************************************************************
1433 * GOVERNORS *
1434 *********************************************************************/
1435
1436
1437int __cpufreq_driver_target(struct cpufreq_policy *policy,
1438 unsigned int target_freq,
1439 unsigned int relation)
1440{
1441 int retval = -EINVAL;
1442
1443 pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
1444 target_freq, relation);
1445 if (cpu_online(policy->cpu) && cpufreq_driver->target)
1446 retval = cpufreq_driver->target(policy, target_freq, relation);
1447
1448 return retval;
1449}
1450EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1451
1452int cpufreq_driver_target(struct cpufreq_policy *policy,
1453 unsigned int target_freq,
1454 unsigned int relation)
1455{
1456 int ret = -EINVAL;
1457
1458 policy = cpufreq_cpu_get(policy->cpu);
1459 if (!policy)
1460 goto no_policy;
1461
1462 if (unlikely(lock_policy_rwsem_write(policy->cpu)))
1463 goto fail;
1464
1465 ret = __cpufreq_driver_target(policy, target_freq, relation);
1466
1467 unlock_policy_rwsem_write(policy->cpu);
1468
1469fail:
1470 cpufreq_cpu_put(policy);
1471no_policy:
1472 return ret;
1473}
1474EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1475
1476int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu)
1477{
1478 int ret = 0;
1479
1480 policy = cpufreq_cpu_get(policy->cpu);
1481 if (!policy)
1482 return -EINVAL;
1483
1484 if (cpu_online(cpu) && cpufreq_driver->getavg)
1485 ret = cpufreq_driver->getavg(policy, cpu);
1486
1487 cpufreq_cpu_put(policy);
1488 return ret;
1489}
1490EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg);
1491
1492/*
1493 * when "event" is CPUFREQ_GOV_LIMITS
1494 */
1495
1496static int __cpufreq_governor(struct cpufreq_policy *policy,
1497 unsigned int event)
1498{
1499 int ret;
1500
1501 /* Only must be defined when default governor is known to have latency
1502 restrictions, like e.g. conservative or ondemand.
1503 That this is the case is already ensured in Kconfig
1504 */
1505#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1506 struct cpufreq_governor *gov = &cpufreq_gov_performance;
1507#else
1508 struct cpufreq_governor *gov = NULL;
1509#endif
1510
1511 if (policy->governor->max_transition_latency &&
1512 policy->cpuinfo.transition_latency >
1513 policy->governor->max_transition_latency) {
1514 if (!gov)
1515 return -EINVAL;
1516 else {
1517 printk(KERN_WARNING "%s governor failed, too long"
1518 " transition latency of HW, fallback"
1519 " to %s governor\n",
1520 policy->governor->name,
1521 gov->name);
1522 policy->governor = gov;
1523 }
1524 }
1525
1526 if (!try_module_get(policy->governor->owner))
1527 return -EINVAL;
1528
1529 pr_debug("__cpufreq_governor for CPU %u, event %u\n",
1530 policy->cpu, event);
1531 ret = policy->governor->governor(policy, event);
1532
1533 /* we keep one module reference alive for
1534 each CPU governed by this CPU */
1535 if ((event != CPUFREQ_GOV_START) || ret)
1536 module_put(policy->governor->owner);
1537 if ((event == CPUFREQ_GOV_STOP) && !ret)
1538 module_put(policy->governor->owner);
1539
1540 return ret;
1541}
1542
1543
1544int cpufreq_register_governor(struct cpufreq_governor *governor)
1545{
1546 int err;
1547
1548 if (!governor)
1549 return -EINVAL;
1550
1551 mutex_lock(&cpufreq_governor_mutex);
1552
1553 err = -EBUSY;
1554 if (__find_governor(governor->name) == NULL) {
1555 err = 0;
1556 list_add(&governor->governor_list, &cpufreq_governor_list);
1557 }
1558
1559 mutex_unlock(&cpufreq_governor_mutex);
1560 return err;
1561}
1562EXPORT_SYMBOL_GPL(cpufreq_register_governor);
1563
1564
1565void cpufreq_unregister_governor(struct cpufreq_governor *governor)
1566{
1567#ifdef CONFIG_HOTPLUG_CPU
1568 int cpu;
1569#endif
1570
1571 if (!governor)
1572 return;
1573
1574#ifdef CONFIG_HOTPLUG_CPU
1575 for_each_present_cpu(cpu) {
1576 if (cpu_online(cpu))
1577 continue;
1578 if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
1579 strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
1580 }
1581#endif
1582
1583 mutex_lock(&cpufreq_governor_mutex);
1584 list_del(&governor->governor_list);
1585 mutex_unlock(&cpufreq_governor_mutex);
1586 return;
1587}
1588EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
1589
1590
1591
1592/*********************************************************************
1593 * POLICY INTERFACE *
1594 *********************************************************************/
1595
1596/**
1597 * cpufreq_get_policy - get the current cpufreq_policy
1598 * @policy: struct cpufreq_policy into which the current cpufreq_policy
1599 * is written
1600 *
1601 * Reads the current cpufreq policy.
1602 */
1603int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
1604{
1605 struct cpufreq_policy *cpu_policy;
1606 if (!policy)
1607 return -EINVAL;
1608
1609 cpu_policy = cpufreq_cpu_get(cpu);
1610 if (!cpu_policy)
1611 return -EINVAL;
1612
1613 memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy));
1614
1615 cpufreq_cpu_put(cpu_policy);
1616 return 0;
1617}
1618EXPORT_SYMBOL(cpufreq_get_policy);
1619
1620
1621/*
1622 * data : current policy.
1623 * policy : policy to be set.
1624 */
1625static int __cpufreq_set_policy(struct cpufreq_policy *data,
1626 struct cpufreq_policy *policy)
1627{
1628 int ret = 0;
1629
1630 pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu,
1631 policy->min, policy->max);
1632
1633 memcpy(&policy->cpuinfo, &data->cpuinfo,
1634 sizeof(struct cpufreq_cpuinfo));
1635
1636 if (policy->min > data->max || policy->max < data->min) {
1637 ret = -EINVAL;
1638 goto error_out;
1639 }
1640
1641 /* verify the cpu speed can be set within this limit */
1642 ret = cpufreq_driver->verify(policy);
1643 if (ret)
1644 goto error_out;
1645
1646 /* adjust if necessary - all reasons */
1647 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1648 CPUFREQ_ADJUST, policy);
1649
1650 /* adjust if necessary - hardware incompatibility*/
1651 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1652 CPUFREQ_INCOMPATIBLE, policy);
1653
1654 /* verify the cpu speed can be set within this limit,
1655 which might be different to the first one */
1656 ret = cpufreq_driver->verify(policy);
1657 if (ret)
1658 goto error_out;
1659
1660 /* notification of the new policy */
1661 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1662 CPUFREQ_NOTIFY, policy);
1663
1664 data->min = policy->min;
1665 data->max = policy->max;
1666
1667 pr_debug("new min and max freqs are %u - %u kHz\n",
1668 data->min, data->max);
1669
1670 if (cpufreq_driver->setpolicy) {
1671 data->policy = policy->policy;
1672 pr_debug("setting range\n");
1673 ret = cpufreq_driver->setpolicy(policy);
1674 } else {
1675 if (policy->governor != data->governor) {
1676 /* save old, working values */
1677 struct cpufreq_governor *old_gov = data->governor;
1678
1679 pr_debug("governor switch\n");
1680
1681 /* end old governor */
1682 if (data->governor)
1683 __cpufreq_governor(data, CPUFREQ_GOV_STOP);
1684
1685 /* start new governor */
1686 data->governor = policy->governor;
1687 if (__cpufreq_governor(data, CPUFREQ_GOV_START)) {
1688 /* new governor failed, so re-start old one */
1689 pr_debug("starting governor %s failed\n",
1690 data->governor->name);
1691 if (old_gov) {
1692 data->governor = old_gov;
1693 __cpufreq_governor(data,
1694 CPUFREQ_GOV_START);
1695 }
1696 ret = -EINVAL;
1697 goto error_out;
1698 }
1699 /* might be a policy change, too, so fall through */
1700 }
1701 pr_debug("governor: change or update limits\n");
1702 __cpufreq_governor(data, CPUFREQ_GOV_LIMITS);
1703 }
1704
1705error_out:
1706 return ret;
1707}
1708
1709/**
1710 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
1711 * @cpu: CPU which shall be re-evaluated
1712 *
1713 * Useful for policy notifiers which have different necessities
1714 * at different times.
1715 */
1716int cpufreq_update_policy(unsigned int cpu)
1717{
1718 struct cpufreq_policy *data = cpufreq_cpu_get(cpu);
1719 struct cpufreq_policy policy;
1720 int ret;
1721
1722 if (!data) {
1723 ret = -ENODEV;
1724 goto no_policy;
1725 }
1726
1727 if (unlikely(lock_policy_rwsem_write(cpu))) {
1728 ret = -EINVAL;
1729 goto fail;
1730 }
1731
1732 pr_debug("updating policy for CPU %u\n", cpu);
1733 memcpy(&policy, data, sizeof(struct cpufreq_policy));
1734 policy.min = data->user_policy.min;
1735 policy.max = data->user_policy.max;
1736 policy.policy = data->user_policy.policy;
1737 policy.governor = data->user_policy.governor;
1738
1739 /* BIOS might change freq behind our back
1740 -> ask driver for current freq and notify governors about a change */
1741 if (cpufreq_driver->get) {
1742 policy.cur = cpufreq_driver->get(cpu);
1743 if (!data->cur) {
1744 pr_debug("Driver did not initialize current freq");
1745 data->cur = policy.cur;
1746 } else {
1747 if (data->cur != policy.cur)
1748 cpufreq_out_of_sync(cpu, data->cur,
1749 policy.cur);
1750 }
1751 }
1752
1753 ret = __cpufreq_set_policy(data, &policy);
1754
1755 unlock_policy_rwsem_write(cpu);
1756
1757fail:
1758 cpufreq_cpu_put(data);
1759no_policy:
1760 return ret;
1761}
1762EXPORT_SYMBOL(cpufreq_update_policy);
1763
1764static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,
1765 unsigned long action, void *hcpu)
1766{
1767 unsigned int cpu = (unsigned long)hcpu;
1768 struct sys_device *sys_dev;
1769
1770 sys_dev = get_cpu_sysdev(cpu);
1771 if (sys_dev) {
1772 switch (action) {
1773 case CPU_ONLINE:
1774 case CPU_ONLINE_FROZEN:
1775 cpufreq_add_dev(sys_dev);
1776 break;
1777 case CPU_DOWN_PREPARE:
1778 case CPU_DOWN_PREPARE_FROZEN:
1779 if (unlikely(lock_policy_rwsem_write(cpu)))
1780 BUG();
1781
1782 __cpufreq_remove_dev(sys_dev);
1783 break;
1784 case CPU_DOWN_FAILED:
1785 case CPU_DOWN_FAILED_FROZEN:
1786 cpufreq_add_dev(sys_dev);
1787 break;
1788 }
1789 }
1790 return NOTIFY_OK;
1791}
1792
1793static struct notifier_block __refdata cpufreq_cpu_notifier = {
1794 .notifier_call = cpufreq_cpu_callback,
1795};
1796
1797/*********************************************************************
1798 * REGISTER / UNREGISTER CPUFREQ DRIVER *
1799 *********************************************************************/
1800
1801/**
1802 * cpufreq_register_driver - register a CPU Frequency driver
1803 * @driver_data: A struct cpufreq_driver containing the values#
1804 * submitted by the CPU Frequency driver.
1805 *
1806 * Registers a CPU Frequency driver to this core code. This code
1807 * returns zero on success, -EBUSY when another driver got here first
1808 * (and isn't unregistered in the meantime).
1809 *
1810 */
1811int cpufreq_register_driver(struct cpufreq_driver *driver_data)
1812{
1813 unsigned long flags;
1814 int ret;
1815
1816 if (!driver_data || !driver_data->verify || !driver_data->init ||
1817 ((!driver_data->setpolicy) && (!driver_data->target)))
1818 return -EINVAL;
1819
1820 pr_debug("trying to register driver %s\n", driver_data->name);
1821
1822 if (driver_data->setpolicy)
1823 driver_data->flags |= CPUFREQ_CONST_LOOPS;
1824
1825 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1826 if (cpufreq_driver) {
1827 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1828 return -EBUSY;
1829 }
1830 cpufreq_driver = driver_data;
1831 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1832
1833 ret = sysdev_driver_register(&cpu_sysdev_class,
1834 &cpufreq_sysdev_driver);
1835 if (ret)
1836 goto err_null_driver;
1837
1838 if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
1839 int i;
1840 ret = -ENODEV;
1841
1842 /* check for at least one working CPU */
1843 for (i = 0; i < nr_cpu_ids; i++)
1844 if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
1845 ret = 0;
1846 break;
1847 }
1848
1849 /* if all ->init() calls failed, unregister */
1850 if (ret) {
1851 pr_debug("no CPU initialized for driver %s\n",
1852 driver_data->name);
1853 goto err_sysdev_unreg;
1854 }
1855 }
1856
1857 register_hotcpu_notifier(&cpufreq_cpu_notifier);
1858 pr_debug("driver %s up and running\n", driver_data->name);
1859
1860 return 0;
1861err_sysdev_unreg:
1862 sysdev_driver_unregister(&cpu_sysdev_class,
1863 &cpufreq_sysdev_driver);
1864err_null_driver:
1865 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1866 cpufreq_driver = NULL;
1867 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1868 return ret;
1869}
1870EXPORT_SYMBOL_GPL(cpufreq_register_driver);
1871
1872
1873/**
1874 * cpufreq_unregister_driver - unregister the current CPUFreq driver
1875 *
1876 * Unregister the current CPUFreq driver. Only call this if you have
1877 * the right to do so, i.e. if you have succeeded in initialising before!
1878 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
1879 * currently not initialised.
1880 */
1881int cpufreq_unregister_driver(struct cpufreq_driver *driver)
1882{
1883 unsigned long flags;
1884
1885 if (!cpufreq_driver || (driver != cpufreq_driver))
1886 return -EINVAL;
1887
1888 pr_debug("unregistering driver %s\n", driver->name);
1889
1890 sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
1891 unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
1892
1893 spin_lock_irqsave(&cpufreq_driver_lock, flags);
1894 cpufreq_driver = NULL;
1895 spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
1896
1897 return 0;
1898}
1899EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
1900
1901static int __init cpufreq_core_init(void)
1902{
1903 int cpu;
1904
1905 for_each_possible_cpu(cpu) {
1906 per_cpu(cpufreq_policy_cpu, cpu) = -1;
1907 init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
1908 }
1909
1910 cpufreq_global_kobject = kobject_create_and_add("cpufreq",
1911 &cpu_sysdev_class.kset.kobj);
1912 BUG_ON(!cpufreq_global_kobject);
1913 register_syscore_ops(&cpufreq_syscore_ops);
1914
1915 return 0;
1916}
1917core_initcall(cpufreq_core_init);
1/*
2 * linux/drivers/cpufreq/cpufreq.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
6 * (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
7 *
8 * Oct 2005 - Ashok Raj <ashok.raj@intel.com>
9 * Added handling for CPU hotplug
10 * Feb 2006 - Jacob Shin <jacob.shin@amd.com>
11 * Fix handling for CPU hotplug -- affected CPUs
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/cpu.h>
21#include <linux/cpufreq.h>
22#include <linux/delay.h>
23#include <linux/device.h>
24#include <linux/init.h>
25#include <linux/kernel_stat.h>
26#include <linux/module.h>
27#include <linux/mutex.h>
28#include <linux/slab.h>
29#include <linux/suspend.h>
30#include <linux/syscore_ops.h>
31#include <linux/tick.h>
32#include <trace/events/power.h>
33
34static LIST_HEAD(cpufreq_policy_list);
35
36static inline bool policy_is_inactive(struct cpufreq_policy *policy)
37{
38 return cpumask_empty(policy->cpus);
39}
40
41/* Macros to iterate over CPU policies */
42#define for_each_suitable_policy(__policy, __active) \
43 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
44 if ((__active) == !policy_is_inactive(__policy))
45
46#define for_each_active_policy(__policy) \
47 for_each_suitable_policy(__policy, true)
48#define for_each_inactive_policy(__policy) \
49 for_each_suitable_policy(__policy, false)
50
51#define for_each_policy(__policy) \
52 list_for_each_entry(__policy, &cpufreq_policy_list, policy_list)
53
54/* Iterate over governors */
55static LIST_HEAD(cpufreq_governor_list);
56#define for_each_governor(__governor) \
57 list_for_each_entry(__governor, &cpufreq_governor_list, governor_list)
58
59/**
60 * The "cpufreq driver" - the arch- or hardware-dependent low
61 * level driver of CPUFreq support, and its spinlock. This lock
62 * also protects the cpufreq_cpu_data array.
63 */
64static struct cpufreq_driver *cpufreq_driver;
65static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
66static DEFINE_RWLOCK(cpufreq_driver_lock);
67
68/* Flag to suspend/resume CPUFreq governors */
69static bool cpufreq_suspended;
70
71static inline bool has_target(void)
72{
73 return cpufreq_driver->target_index || cpufreq_driver->target;
74}
75
76/* internal prototypes */
77static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
78static int cpufreq_init_governor(struct cpufreq_policy *policy);
79static void cpufreq_exit_governor(struct cpufreq_policy *policy);
80static int cpufreq_start_governor(struct cpufreq_policy *policy);
81static void cpufreq_stop_governor(struct cpufreq_policy *policy);
82static void cpufreq_governor_limits(struct cpufreq_policy *policy);
83
84/**
85 * Two notifier lists: the "policy" list is involved in the
86 * validation process for a new CPU frequency policy; the
87 * "transition" list for kernel code that needs to handle
88 * changes to devices when the CPU clock speed changes.
89 * The mutex locks both lists.
90 */
91static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
92static struct srcu_notifier_head cpufreq_transition_notifier_list;
93
94static bool init_cpufreq_transition_notifier_list_called;
95static int __init init_cpufreq_transition_notifier_list(void)
96{
97 srcu_init_notifier_head(&cpufreq_transition_notifier_list);
98 init_cpufreq_transition_notifier_list_called = true;
99 return 0;
100}
101pure_initcall(init_cpufreq_transition_notifier_list);
102
103static int off __read_mostly;
104static int cpufreq_disabled(void)
105{
106 return off;
107}
108void disable_cpufreq(void)
109{
110 off = 1;
111}
112static DEFINE_MUTEX(cpufreq_governor_mutex);
113
114bool have_governor_per_policy(void)
115{
116 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
117}
118EXPORT_SYMBOL_GPL(have_governor_per_policy);
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 u64 idle_time;
132 u64 cur_wall_time;
133 u64 busy_time;
134
135 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
136
137 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
138 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
139 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
140 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
141 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
142 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
143
144 idle_time = cur_wall_time - busy_time;
145 if (wall)
146 *wall = cputime_to_usecs(cur_wall_time);
147
148 return cputime_to_usecs(idle_time);
149}
150
151u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
152{
153 u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
154
155 if (idle_time == -1ULL)
156 return get_cpu_idle_time_jiffy(cpu, wall);
157 else if (!io_busy)
158 idle_time += get_cpu_iowait_time_us(cpu, wall);
159
160 return idle_time;
161}
162EXPORT_SYMBOL_GPL(get_cpu_idle_time);
163
164/*
165 * This is a generic cpufreq init() routine which can be used by cpufreq
166 * drivers of SMP systems. It will do following:
167 * - validate & show freq table passed
168 * - set policies transition latency
169 * - policy->cpus with all possible CPUs
170 */
171int cpufreq_generic_init(struct cpufreq_policy *policy,
172 struct cpufreq_frequency_table *table,
173 unsigned int transition_latency)
174{
175 int ret;
176
177 ret = cpufreq_table_validate_and_show(policy, table);
178 if (ret) {
179 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
180 return ret;
181 }
182
183 policy->cpuinfo.transition_latency = transition_latency;
184
185 /*
186 * The driver only supports the SMP configuration where all processors
187 * share the clock and voltage and clock.
188 */
189 cpumask_setall(policy->cpus);
190
191 return 0;
192}
193EXPORT_SYMBOL_GPL(cpufreq_generic_init);
194
195struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
196{
197 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
198
199 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
200}
201EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
202
203unsigned int cpufreq_generic_get(unsigned int cpu)
204{
205 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
206
207 if (!policy || IS_ERR(policy->clk)) {
208 pr_err("%s: No %s associated to cpu: %d\n",
209 __func__, policy ? "clk" : "policy", cpu);
210 return 0;
211 }
212
213 return clk_get_rate(policy->clk) / 1000;
214}
215EXPORT_SYMBOL_GPL(cpufreq_generic_get);
216
217/**
218 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
219 *
220 * @cpu: cpu to find policy for.
221 *
222 * This returns policy for 'cpu', returns NULL if it doesn't exist.
223 * It also increments the kobject reference count to mark it busy and so would
224 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
225 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
226 * freed as that depends on the kobj count.
227 *
228 * Return: A valid policy on success, otherwise NULL on failure.
229 */
230struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
231{
232 struct cpufreq_policy *policy = NULL;
233 unsigned long flags;
234
235 if (WARN_ON(cpu >= nr_cpu_ids))
236 return NULL;
237
238 /* get the cpufreq driver */
239 read_lock_irqsave(&cpufreq_driver_lock, flags);
240
241 if (cpufreq_driver) {
242 /* get the CPU */
243 policy = cpufreq_cpu_get_raw(cpu);
244 if (policy)
245 kobject_get(&policy->kobj);
246 }
247
248 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
249
250 return policy;
251}
252EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
253
254/**
255 * cpufreq_cpu_put: Decrements the usage count of a policy
256 *
257 * @policy: policy earlier returned by cpufreq_cpu_get().
258 *
259 * This decrements the kobject reference count incremented earlier by calling
260 * cpufreq_cpu_get().
261 */
262void cpufreq_cpu_put(struct cpufreq_policy *policy)
263{
264 kobject_put(&policy->kobj);
265}
266EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
267
268/*********************************************************************
269 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
270 *********************************************************************/
271
272/**
273 * adjust_jiffies - adjust the system "loops_per_jiffy"
274 *
275 * This function alters the system "loops_per_jiffy" for the clock
276 * speed change. Note that loops_per_jiffy cannot be updated on SMP
277 * systems as each CPU might be scaled differently. So, use the arch
278 * per-CPU loops_per_jiffy value wherever possible.
279 */
280static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
281{
282#ifndef CONFIG_SMP
283 static unsigned long l_p_j_ref;
284 static unsigned int l_p_j_ref_freq;
285
286 if (ci->flags & CPUFREQ_CONST_LOOPS)
287 return;
288
289 if (!l_p_j_ref_freq) {
290 l_p_j_ref = loops_per_jiffy;
291 l_p_j_ref_freq = ci->old;
292 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
293 l_p_j_ref, l_p_j_ref_freq);
294 }
295 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
296 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
297 ci->new);
298 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
299 loops_per_jiffy, ci->new);
300 }
301#endif
302}
303
304static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
305 struct cpufreq_freqs *freqs, unsigned int state)
306{
307 BUG_ON(irqs_disabled());
308
309 if (cpufreq_disabled())
310 return;
311
312 freqs->flags = cpufreq_driver->flags;
313 pr_debug("notification %u of frequency transition to %u kHz\n",
314 state, freqs->new);
315
316 switch (state) {
317
318 case CPUFREQ_PRECHANGE:
319 /* detect if the driver reported a value as "old frequency"
320 * which is not equal to what the cpufreq core thinks is
321 * "old frequency".
322 */
323 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
324 if ((policy) && (policy->cpu == freqs->cpu) &&
325 (policy->cur) && (policy->cur != freqs->old)) {
326 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
327 freqs->old, policy->cur);
328 freqs->old = policy->cur;
329 }
330 }
331 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
332 CPUFREQ_PRECHANGE, freqs);
333 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
334 break;
335
336 case CPUFREQ_POSTCHANGE:
337 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
338 pr_debug("FREQ: %lu - CPU: %lu\n",
339 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
340 trace_cpu_frequency(freqs->new, freqs->cpu);
341 cpufreq_stats_record_transition(policy, freqs->new);
342 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
343 CPUFREQ_POSTCHANGE, freqs);
344 if (likely(policy) && likely(policy->cpu == freqs->cpu))
345 policy->cur = freqs->new;
346 break;
347 }
348}
349
350/**
351 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
352 * on frequency transition.
353 *
354 * This function calls the transition notifiers and the "adjust_jiffies"
355 * function. It is called twice on all CPU frequency changes that have
356 * external effects.
357 */
358static void cpufreq_notify_transition(struct cpufreq_policy *policy,
359 struct cpufreq_freqs *freqs, unsigned int state)
360{
361 for_each_cpu(freqs->cpu, policy->cpus)
362 __cpufreq_notify_transition(policy, freqs, state);
363}
364
365/* Do post notifications when there are chances that transition has failed */
366static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
367 struct cpufreq_freqs *freqs, int transition_failed)
368{
369 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
370 if (!transition_failed)
371 return;
372
373 swap(freqs->old, freqs->new);
374 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
375 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
376}
377
378void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
379 struct cpufreq_freqs *freqs)
380{
381
382 /*
383 * Catch double invocations of _begin() which lead to self-deadlock.
384 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
385 * doesn't invoke _begin() on their behalf, and hence the chances of
386 * double invocations are very low. Moreover, there are scenarios
387 * where these checks can emit false-positive warnings in these
388 * drivers; so we avoid that by skipping them altogether.
389 */
390 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
391 && current == policy->transition_task);
392
393wait:
394 wait_event(policy->transition_wait, !policy->transition_ongoing);
395
396 spin_lock(&policy->transition_lock);
397
398 if (unlikely(policy->transition_ongoing)) {
399 spin_unlock(&policy->transition_lock);
400 goto wait;
401 }
402
403 policy->transition_ongoing = true;
404 policy->transition_task = current;
405
406 spin_unlock(&policy->transition_lock);
407
408 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
409}
410EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
411
412void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
413 struct cpufreq_freqs *freqs, int transition_failed)
414{
415 if (unlikely(WARN_ON(!policy->transition_ongoing)))
416 return;
417
418 cpufreq_notify_post_transition(policy, freqs, transition_failed);
419
420 policy->transition_ongoing = false;
421 policy->transition_task = NULL;
422
423 wake_up(&policy->transition_wait);
424}
425EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
426
427/*
428 * Fast frequency switching status count. Positive means "enabled", negative
429 * means "disabled" and 0 means "not decided yet".
430 */
431static int cpufreq_fast_switch_count;
432static DEFINE_MUTEX(cpufreq_fast_switch_lock);
433
434static void cpufreq_list_transition_notifiers(void)
435{
436 struct notifier_block *nb;
437
438 pr_info("Registered transition notifiers:\n");
439
440 mutex_lock(&cpufreq_transition_notifier_list.mutex);
441
442 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
443 pr_info("%pF\n", nb->notifier_call);
444
445 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
446}
447
448/**
449 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
450 * @policy: cpufreq policy to enable fast frequency switching for.
451 *
452 * Try to enable fast frequency switching for @policy.
453 *
454 * The attempt will fail if there is at least one transition notifier registered
455 * at this point, as fast frequency switching is quite fundamentally at odds
456 * with transition notifiers. Thus if successful, it will make registration of
457 * transition notifiers fail going forward.
458 */
459void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
460{
461 lockdep_assert_held(&policy->rwsem);
462
463 if (!policy->fast_switch_possible)
464 return;
465
466 mutex_lock(&cpufreq_fast_switch_lock);
467 if (cpufreq_fast_switch_count >= 0) {
468 cpufreq_fast_switch_count++;
469 policy->fast_switch_enabled = true;
470 } else {
471 pr_warn("CPU%u: Fast frequency switching not enabled\n",
472 policy->cpu);
473 cpufreq_list_transition_notifiers();
474 }
475 mutex_unlock(&cpufreq_fast_switch_lock);
476}
477EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
478
479/**
480 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
481 * @policy: cpufreq policy to disable fast frequency switching for.
482 */
483void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
484{
485 mutex_lock(&cpufreq_fast_switch_lock);
486 if (policy->fast_switch_enabled) {
487 policy->fast_switch_enabled = false;
488 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
489 cpufreq_fast_switch_count--;
490 }
491 mutex_unlock(&cpufreq_fast_switch_lock);
492}
493EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
494
495/**
496 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
497 * one.
498 * @target_freq: target frequency to resolve.
499 *
500 * The target to driver frequency mapping is cached in the policy.
501 *
502 * Return: Lowest driver-supported frequency greater than or equal to the
503 * given target_freq, subject to policy (min/max) and driver limitations.
504 */
505unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
506 unsigned int target_freq)
507{
508 target_freq = clamp_val(target_freq, policy->min, policy->max);
509 policy->cached_target_freq = target_freq;
510
511 if (cpufreq_driver->target_index) {
512 int idx;
513
514 idx = cpufreq_frequency_table_target(policy, target_freq,
515 CPUFREQ_RELATION_L);
516 policy->cached_resolved_idx = idx;
517 return policy->freq_table[idx].frequency;
518 }
519
520 if (cpufreq_driver->resolve_freq)
521 return cpufreq_driver->resolve_freq(policy, target_freq);
522
523 return target_freq;
524}
525EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
526
527/*********************************************************************
528 * SYSFS INTERFACE *
529 *********************************************************************/
530static ssize_t show_boost(struct kobject *kobj,
531 struct attribute *attr, char *buf)
532{
533 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
534}
535
536static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
537 const char *buf, size_t count)
538{
539 int ret, enable;
540
541 ret = sscanf(buf, "%d", &enable);
542 if (ret != 1 || enable < 0 || enable > 1)
543 return -EINVAL;
544
545 if (cpufreq_boost_trigger_state(enable)) {
546 pr_err("%s: Cannot %s BOOST!\n",
547 __func__, enable ? "enable" : "disable");
548 return -EINVAL;
549 }
550
551 pr_debug("%s: cpufreq BOOST %s\n",
552 __func__, enable ? "enabled" : "disabled");
553
554 return count;
555}
556define_one_global_rw(boost);
557
558static struct cpufreq_governor *find_governor(const char *str_governor)
559{
560 struct cpufreq_governor *t;
561
562 for_each_governor(t)
563 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
564 return t;
565
566 return NULL;
567}
568
569/**
570 * cpufreq_parse_governor - parse a governor string
571 */
572static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
573 struct cpufreq_governor **governor)
574{
575 int err = -EINVAL;
576
577 if (cpufreq_driver->setpolicy) {
578 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
579 *policy = CPUFREQ_POLICY_PERFORMANCE;
580 err = 0;
581 } else if (!strncasecmp(str_governor, "powersave",
582 CPUFREQ_NAME_LEN)) {
583 *policy = CPUFREQ_POLICY_POWERSAVE;
584 err = 0;
585 }
586 } else {
587 struct cpufreq_governor *t;
588
589 mutex_lock(&cpufreq_governor_mutex);
590
591 t = find_governor(str_governor);
592
593 if (t == NULL) {
594 int ret;
595
596 mutex_unlock(&cpufreq_governor_mutex);
597 ret = request_module("cpufreq_%s", str_governor);
598 mutex_lock(&cpufreq_governor_mutex);
599
600 if (ret == 0)
601 t = find_governor(str_governor);
602 }
603
604 if (t != NULL) {
605 *governor = t;
606 err = 0;
607 }
608
609 mutex_unlock(&cpufreq_governor_mutex);
610 }
611 return err;
612}
613
614/**
615 * cpufreq_per_cpu_attr_read() / show_##file_name() -
616 * print out cpufreq information
617 *
618 * Write out information from cpufreq_driver->policy[cpu]; object must be
619 * "unsigned int".
620 */
621
622#define show_one(file_name, object) \
623static ssize_t show_##file_name \
624(struct cpufreq_policy *policy, char *buf) \
625{ \
626 return sprintf(buf, "%u\n", policy->object); \
627}
628
629show_one(cpuinfo_min_freq, cpuinfo.min_freq);
630show_one(cpuinfo_max_freq, cpuinfo.max_freq);
631show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
632show_one(scaling_min_freq, min);
633show_one(scaling_max_freq, max);
634
635static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
636{
637 ssize_t ret;
638
639 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
640 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
641 else
642 ret = sprintf(buf, "%u\n", policy->cur);
643 return ret;
644}
645
646static int cpufreq_set_policy(struct cpufreq_policy *policy,
647 struct cpufreq_policy *new_policy);
648
649/**
650 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
651 */
652#define store_one(file_name, object) \
653static ssize_t store_##file_name \
654(struct cpufreq_policy *policy, const char *buf, size_t count) \
655{ \
656 int ret, temp; \
657 struct cpufreq_policy new_policy; \
658 \
659 memcpy(&new_policy, policy, sizeof(*policy)); \
660 \
661 ret = sscanf(buf, "%u", &new_policy.object); \
662 if (ret != 1) \
663 return -EINVAL; \
664 \
665 temp = new_policy.object; \
666 ret = cpufreq_set_policy(policy, &new_policy); \
667 if (!ret) \
668 policy->user_policy.object = temp; \
669 \
670 return ret ? ret : count; \
671}
672
673store_one(scaling_min_freq, min);
674store_one(scaling_max_freq, max);
675
676/**
677 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
678 */
679static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
680 char *buf)
681{
682 unsigned int cur_freq = __cpufreq_get(policy);
683
684 if (cur_freq)
685 return sprintf(buf, "%u\n", cur_freq);
686
687 return sprintf(buf, "<unknown>\n");
688}
689
690/**
691 * show_scaling_governor - show the current policy for the specified CPU
692 */
693static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
694{
695 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
696 return sprintf(buf, "powersave\n");
697 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
698 return sprintf(buf, "performance\n");
699 else if (policy->governor)
700 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
701 policy->governor->name);
702 return -EINVAL;
703}
704
705/**
706 * store_scaling_governor - store policy for the specified CPU
707 */
708static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
709 const char *buf, size_t count)
710{
711 int ret;
712 char str_governor[16];
713 struct cpufreq_policy new_policy;
714
715 memcpy(&new_policy, policy, sizeof(*policy));
716
717 ret = sscanf(buf, "%15s", str_governor);
718 if (ret != 1)
719 return -EINVAL;
720
721 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
722 &new_policy.governor))
723 return -EINVAL;
724
725 ret = cpufreq_set_policy(policy, &new_policy);
726 return ret ? ret : count;
727}
728
729/**
730 * show_scaling_driver - show the cpufreq driver currently loaded
731 */
732static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
733{
734 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
735}
736
737/**
738 * show_scaling_available_governors - show the available CPUfreq governors
739 */
740static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
741 char *buf)
742{
743 ssize_t i = 0;
744 struct cpufreq_governor *t;
745
746 if (!has_target()) {
747 i += sprintf(buf, "performance powersave");
748 goto out;
749 }
750
751 for_each_governor(t) {
752 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
753 - (CPUFREQ_NAME_LEN + 2)))
754 goto out;
755 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
756 }
757out:
758 i += sprintf(&buf[i], "\n");
759 return i;
760}
761
762ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
763{
764 ssize_t i = 0;
765 unsigned int cpu;
766
767 for_each_cpu(cpu, mask) {
768 if (i)
769 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
770 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
771 if (i >= (PAGE_SIZE - 5))
772 break;
773 }
774 i += sprintf(&buf[i], "\n");
775 return i;
776}
777EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
778
779/**
780 * show_related_cpus - show the CPUs affected by each transition even if
781 * hw coordination is in use
782 */
783static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
784{
785 return cpufreq_show_cpus(policy->related_cpus, buf);
786}
787
788/**
789 * show_affected_cpus - show the CPUs affected by each transition
790 */
791static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
792{
793 return cpufreq_show_cpus(policy->cpus, buf);
794}
795
796static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
797 const char *buf, size_t count)
798{
799 unsigned int freq = 0;
800 unsigned int ret;
801
802 if (!policy->governor || !policy->governor->store_setspeed)
803 return -EINVAL;
804
805 ret = sscanf(buf, "%u", &freq);
806 if (ret != 1)
807 return -EINVAL;
808
809 policy->governor->store_setspeed(policy, freq);
810
811 return count;
812}
813
814static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
815{
816 if (!policy->governor || !policy->governor->show_setspeed)
817 return sprintf(buf, "<unsupported>\n");
818
819 return policy->governor->show_setspeed(policy, buf);
820}
821
822/**
823 * show_bios_limit - show the current cpufreq HW/BIOS limitation
824 */
825static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
826{
827 unsigned int limit;
828 int ret;
829 if (cpufreq_driver->bios_limit) {
830 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
831 if (!ret)
832 return sprintf(buf, "%u\n", limit);
833 }
834 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
835}
836
837cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
838cpufreq_freq_attr_ro(cpuinfo_min_freq);
839cpufreq_freq_attr_ro(cpuinfo_max_freq);
840cpufreq_freq_attr_ro(cpuinfo_transition_latency);
841cpufreq_freq_attr_ro(scaling_available_governors);
842cpufreq_freq_attr_ro(scaling_driver);
843cpufreq_freq_attr_ro(scaling_cur_freq);
844cpufreq_freq_attr_ro(bios_limit);
845cpufreq_freq_attr_ro(related_cpus);
846cpufreq_freq_attr_ro(affected_cpus);
847cpufreq_freq_attr_rw(scaling_min_freq);
848cpufreq_freq_attr_rw(scaling_max_freq);
849cpufreq_freq_attr_rw(scaling_governor);
850cpufreq_freq_attr_rw(scaling_setspeed);
851
852static struct attribute *default_attrs[] = {
853 &cpuinfo_min_freq.attr,
854 &cpuinfo_max_freq.attr,
855 &cpuinfo_transition_latency.attr,
856 &scaling_min_freq.attr,
857 &scaling_max_freq.attr,
858 &affected_cpus.attr,
859 &related_cpus.attr,
860 &scaling_governor.attr,
861 &scaling_driver.attr,
862 &scaling_available_governors.attr,
863 &scaling_setspeed.attr,
864 NULL
865};
866
867#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
868#define to_attr(a) container_of(a, struct freq_attr, attr)
869
870static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
871{
872 struct cpufreq_policy *policy = to_policy(kobj);
873 struct freq_attr *fattr = to_attr(attr);
874 ssize_t ret;
875
876 down_read(&policy->rwsem);
877 ret = fattr->show(policy, buf);
878 up_read(&policy->rwsem);
879
880 return ret;
881}
882
883static ssize_t store(struct kobject *kobj, struct attribute *attr,
884 const char *buf, size_t count)
885{
886 struct cpufreq_policy *policy = to_policy(kobj);
887 struct freq_attr *fattr = to_attr(attr);
888 ssize_t ret = -EINVAL;
889
890 get_online_cpus();
891
892 if (cpu_online(policy->cpu)) {
893 down_write(&policy->rwsem);
894 ret = fattr->store(policy, buf, count);
895 up_write(&policy->rwsem);
896 }
897
898 put_online_cpus();
899
900 return ret;
901}
902
903static void cpufreq_sysfs_release(struct kobject *kobj)
904{
905 struct cpufreq_policy *policy = to_policy(kobj);
906 pr_debug("last reference is dropped\n");
907 complete(&policy->kobj_unregister);
908}
909
910static const struct sysfs_ops sysfs_ops = {
911 .show = show,
912 .store = store,
913};
914
915static struct kobj_type ktype_cpufreq = {
916 .sysfs_ops = &sysfs_ops,
917 .default_attrs = default_attrs,
918 .release = cpufreq_sysfs_release,
919};
920
921static int add_cpu_dev_symlink(struct cpufreq_policy *policy,
922 struct device *dev)
923{
924 dev_dbg(dev, "%s: Adding symlink\n", __func__);
925 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
926}
927
928static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
929 struct device *dev)
930{
931 dev_dbg(dev, "%s: Removing symlink\n", __func__);
932 sysfs_remove_link(&dev->kobj, "cpufreq");
933}
934
935static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
936{
937 struct freq_attr **drv_attr;
938 int ret = 0;
939
940 /* set up files for this cpu device */
941 drv_attr = cpufreq_driver->attr;
942 while (drv_attr && *drv_attr) {
943 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
944 if (ret)
945 return ret;
946 drv_attr++;
947 }
948 if (cpufreq_driver->get) {
949 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
950 if (ret)
951 return ret;
952 }
953
954 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
955 if (ret)
956 return ret;
957
958 if (cpufreq_driver->bios_limit) {
959 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
960 if (ret)
961 return ret;
962 }
963
964 return 0;
965}
966
967__weak struct cpufreq_governor *cpufreq_default_governor(void)
968{
969 return NULL;
970}
971
972static int cpufreq_init_policy(struct cpufreq_policy *policy)
973{
974 struct cpufreq_governor *gov = NULL;
975 struct cpufreq_policy new_policy;
976
977 memcpy(&new_policy, policy, sizeof(*policy));
978
979 /* Update governor of new_policy to the governor used before hotplug */
980 gov = find_governor(policy->last_governor);
981 if (gov) {
982 pr_debug("Restoring governor %s for cpu %d\n",
983 policy->governor->name, policy->cpu);
984 } else {
985 gov = cpufreq_default_governor();
986 if (!gov)
987 return -ENODATA;
988 }
989
990 new_policy.governor = gov;
991
992 /* Use the default policy if there is no last_policy. */
993 if (cpufreq_driver->setpolicy) {
994 if (policy->last_policy)
995 new_policy.policy = policy->last_policy;
996 else
997 cpufreq_parse_governor(gov->name, &new_policy.policy,
998 NULL);
999 }
1000 /* set default policy */
1001 return cpufreq_set_policy(policy, &new_policy);
1002}
1003
1004static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1005{
1006 int ret = 0;
1007
1008 /* Has this CPU been taken care of already? */
1009 if (cpumask_test_cpu(cpu, policy->cpus))
1010 return 0;
1011
1012 down_write(&policy->rwsem);
1013 if (has_target())
1014 cpufreq_stop_governor(policy);
1015
1016 cpumask_set_cpu(cpu, policy->cpus);
1017
1018 if (has_target()) {
1019 ret = cpufreq_start_governor(policy);
1020 if (ret)
1021 pr_err("%s: Failed to start governor\n", __func__);
1022 }
1023 up_write(&policy->rwsem);
1024 return ret;
1025}
1026
1027static void handle_update(struct work_struct *work)
1028{
1029 struct cpufreq_policy *policy =
1030 container_of(work, struct cpufreq_policy, update);
1031 unsigned int cpu = policy->cpu;
1032 pr_debug("handle_update for cpu %u called\n", cpu);
1033 cpufreq_update_policy(cpu);
1034}
1035
1036static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1037{
1038 struct cpufreq_policy *policy;
1039 int ret;
1040
1041 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1042 if (!policy)
1043 return NULL;
1044
1045 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1046 goto err_free_policy;
1047
1048 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1049 goto err_free_cpumask;
1050
1051 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1052 goto err_free_rcpumask;
1053
1054 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1055 cpufreq_global_kobject, "policy%u", cpu);
1056 if (ret) {
1057 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1058 goto err_free_real_cpus;
1059 }
1060
1061 INIT_LIST_HEAD(&policy->policy_list);
1062 init_rwsem(&policy->rwsem);
1063 spin_lock_init(&policy->transition_lock);
1064 init_waitqueue_head(&policy->transition_wait);
1065 init_completion(&policy->kobj_unregister);
1066 INIT_WORK(&policy->update, handle_update);
1067
1068 policy->cpu = cpu;
1069 return policy;
1070
1071err_free_real_cpus:
1072 free_cpumask_var(policy->real_cpus);
1073err_free_rcpumask:
1074 free_cpumask_var(policy->related_cpus);
1075err_free_cpumask:
1076 free_cpumask_var(policy->cpus);
1077err_free_policy:
1078 kfree(policy);
1079
1080 return NULL;
1081}
1082
1083static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1084{
1085 struct kobject *kobj;
1086 struct completion *cmp;
1087
1088 if (notify)
1089 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1090 CPUFREQ_REMOVE_POLICY, policy);
1091
1092 down_write(&policy->rwsem);
1093 cpufreq_stats_free_table(policy);
1094 kobj = &policy->kobj;
1095 cmp = &policy->kobj_unregister;
1096 up_write(&policy->rwsem);
1097 kobject_put(kobj);
1098
1099 /*
1100 * We need to make sure that the underlying kobj is
1101 * actually not referenced anymore by anybody before we
1102 * proceed with unloading.
1103 */
1104 pr_debug("waiting for dropping of refcount\n");
1105 wait_for_completion(cmp);
1106 pr_debug("wait complete\n");
1107}
1108
1109static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1110{
1111 unsigned long flags;
1112 int cpu;
1113
1114 /* Remove policy from list */
1115 write_lock_irqsave(&cpufreq_driver_lock, flags);
1116 list_del(&policy->policy_list);
1117
1118 for_each_cpu(cpu, policy->related_cpus)
1119 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1120 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1121
1122 cpufreq_policy_put_kobj(policy, notify);
1123 free_cpumask_var(policy->real_cpus);
1124 free_cpumask_var(policy->related_cpus);
1125 free_cpumask_var(policy->cpus);
1126 kfree(policy);
1127}
1128
1129static int cpufreq_online(unsigned int cpu)
1130{
1131 struct cpufreq_policy *policy;
1132 bool new_policy;
1133 unsigned long flags;
1134 unsigned int j;
1135 int ret;
1136
1137 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1138
1139 /* Check if this CPU already has a policy to manage it */
1140 policy = per_cpu(cpufreq_cpu_data, cpu);
1141 if (policy) {
1142 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1143 if (!policy_is_inactive(policy))
1144 return cpufreq_add_policy_cpu(policy, cpu);
1145
1146 /* This is the only online CPU for the policy. Start over. */
1147 new_policy = false;
1148 down_write(&policy->rwsem);
1149 policy->cpu = cpu;
1150 policy->governor = NULL;
1151 up_write(&policy->rwsem);
1152 } else {
1153 new_policy = true;
1154 policy = cpufreq_policy_alloc(cpu);
1155 if (!policy)
1156 return -ENOMEM;
1157 }
1158
1159 cpumask_copy(policy->cpus, cpumask_of(cpu));
1160
1161 /* call driver. From then on the cpufreq must be able
1162 * to accept all calls to ->verify and ->setpolicy for this CPU
1163 */
1164 ret = cpufreq_driver->init(policy);
1165 if (ret) {
1166 pr_debug("initialization failed\n");
1167 goto out_free_policy;
1168 }
1169
1170 down_write(&policy->rwsem);
1171
1172 if (new_policy) {
1173 /* related_cpus should at least include policy->cpus. */
1174 cpumask_copy(policy->related_cpus, policy->cpus);
1175 /* Clear mask of registered CPUs */
1176 cpumask_clear(policy->real_cpus);
1177 }
1178
1179 /*
1180 * affected cpus must always be the one, which are online. We aren't
1181 * managing offline cpus here.
1182 */
1183 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1184
1185 if (new_policy) {
1186 policy->user_policy.min = policy->min;
1187 policy->user_policy.max = policy->max;
1188
1189 write_lock_irqsave(&cpufreq_driver_lock, flags);
1190 for_each_cpu(j, policy->related_cpus)
1191 per_cpu(cpufreq_cpu_data, j) = policy;
1192 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1193 } else {
1194 policy->min = policy->user_policy.min;
1195 policy->max = policy->user_policy.max;
1196 }
1197
1198 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1199 policy->cur = cpufreq_driver->get(policy->cpu);
1200 if (!policy->cur) {
1201 pr_err("%s: ->get() failed\n", __func__);
1202 goto out_exit_policy;
1203 }
1204 }
1205
1206 /*
1207 * Sometimes boot loaders set CPU frequency to a value outside of
1208 * frequency table present with cpufreq core. In such cases CPU might be
1209 * unstable if it has to run on that frequency for long duration of time
1210 * and so its better to set it to a frequency which is specified in
1211 * freq-table. This also makes cpufreq stats inconsistent as
1212 * cpufreq-stats would fail to register because current frequency of CPU
1213 * isn't found in freq-table.
1214 *
1215 * Because we don't want this change to effect boot process badly, we go
1216 * for the next freq which is >= policy->cur ('cur' must be set by now,
1217 * otherwise we will end up setting freq to lowest of the table as 'cur'
1218 * is initialized to zero).
1219 *
1220 * We are passing target-freq as "policy->cur - 1" otherwise
1221 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1222 * equal to target-freq.
1223 */
1224 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1225 && has_target()) {
1226 /* Are we running at unknown frequency ? */
1227 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1228 if (ret == -EINVAL) {
1229 /* Warn user and fix it */
1230 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1231 __func__, policy->cpu, policy->cur);
1232 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1233 CPUFREQ_RELATION_L);
1234
1235 /*
1236 * Reaching here after boot in a few seconds may not
1237 * mean that system will remain stable at "unknown"
1238 * frequency for longer duration. Hence, a BUG_ON().
1239 */
1240 BUG_ON(ret);
1241 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1242 __func__, policy->cpu, policy->cur);
1243 }
1244 }
1245
1246 if (new_policy) {
1247 ret = cpufreq_add_dev_interface(policy);
1248 if (ret)
1249 goto out_exit_policy;
1250
1251 cpufreq_stats_create_table(policy);
1252 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1253 CPUFREQ_CREATE_POLICY, policy);
1254
1255 write_lock_irqsave(&cpufreq_driver_lock, flags);
1256 list_add(&policy->policy_list, &cpufreq_policy_list);
1257 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1258 }
1259
1260 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1261 CPUFREQ_START, policy);
1262
1263 ret = cpufreq_init_policy(policy);
1264 if (ret) {
1265 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1266 __func__, cpu, ret);
1267 /* cpufreq_policy_free() will notify based on this */
1268 new_policy = false;
1269 goto out_exit_policy;
1270 }
1271
1272 up_write(&policy->rwsem);
1273
1274 kobject_uevent(&policy->kobj, KOBJ_ADD);
1275
1276 /* Callback for handling stuff after policy is ready */
1277 if (cpufreq_driver->ready)
1278 cpufreq_driver->ready(policy);
1279
1280 pr_debug("initialization complete\n");
1281
1282 return 0;
1283
1284out_exit_policy:
1285 up_write(&policy->rwsem);
1286
1287 if (cpufreq_driver->exit)
1288 cpufreq_driver->exit(policy);
1289out_free_policy:
1290 cpufreq_policy_free(policy, !new_policy);
1291 return ret;
1292}
1293
1294static int cpufreq_offline(unsigned int cpu);
1295
1296/**
1297 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1298 * @dev: CPU device.
1299 * @sif: Subsystem interface structure pointer (not used)
1300 */
1301static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1302{
1303 struct cpufreq_policy *policy;
1304 unsigned cpu = dev->id;
1305 int ret;
1306
1307 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1308
1309 if (cpu_online(cpu)) {
1310 ret = cpufreq_online(cpu);
1311 if (ret)
1312 return ret;
1313 }
1314
1315 /* Create sysfs link on CPU registration */
1316 policy = per_cpu(cpufreq_cpu_data, cpu);
1317 if (!policy || cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1318 return 0;
1319
1320 ret = add_cpu_dev_symlink(policy, dev);
1321 if (ret) {
1322 cpumask_clear_cpu(cpu, policy->real_cpus);
1323 cpufreq_offline(cpu);
1324 }
1325
1326 return ret;
1327}
1328
1329static int cpufreq_offline(unsigned int cpu)
1330{
1331 struct cpufreq_policy *policy;
1332 int ret;
1333
1334 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1335
1336 policy = cpufreq_cpu_get_raw(cpu);
1337 if (!policy) {
1338 pr_debug("%s: No cpu_data found\n", __func__);
1339 return 0;
1340 }
1341
1342 down_write(&policy->rwsem);
1343 if (has_target())
1344 cpufreq_stop_governor(policy);
1345
1346 cpumask_clear_cpu(cpu, policy->cpus);
1347
1348 if (policy_is_inactive(policy)) {
1349 if (has_target())
1350 strncpy(policy->last_governor, policy->governor->name,
1351 CPUFREQ_NAME_LEN);
1352 else
1353 policy->last_policy = policy->policy;
1354 } else if (cpu == policy->cpu) {
1355 /* Nominate new CPU */
1356 policy->cpu = cpumask_any(policy->cpus);
1357 }
1358
1359 /* Start governor again for active policy */
1360 if (!policy_is_inactive(policy)) {
1361 if (has_target()) {
1362 ret = cpufreq_start_governor(policy);
1363 if (ret)
1364 pr_err("%s: Failed to start governor\n", __func__);
1365 }
1366
1367 goto unlock;
1368 }
1369
1370 if (cpufreq_driver->stop_cpu)
1371 cpufreq_driver->stop_cpu(policy);
1372
1373 if (has_target())
1374 cpufreq_exit_governor(policy);
1375
1376 /*
1377 * Perform the ->exit() even during light-weight tear-down,
1378 * since this is a core component, and is essential for the
1379 * subsequent light-weight ->init() to succeed.
1380 */
1381 if (cpufreq_driver->exit) {
1382 cpufreq_driver->exit(policy);
1383 policy->freq_table = NULL;
1384 }
1385
1386unlock:
1387 up_write(&policy->rwsem);
1388 return 0;
1389}
1390
1391/**
1392 * cpufreq_remove_dev - remove a CPU device
1393 *
1394 * Removes the cpufreq interface for a CPU device.
1395 */
1396static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1397{
1398 unsigned int cpu = dev->id;
1399 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1400
1401 if (!policy)
1402 return;
1403
1404 if (cpu_online(cpu))
1405 cpufreq_offline(cpu);
1406
1407 cpumask_clear_cpu(cpu, policy->real_cpus);
1408 remove_cpu_dev_symlink(policy, dev);
1409
1410 if (cpumask_empty(policy->real_cpus))
1411 cpufreq_policy_free(policy, true);
1412}
1413
1414/**
1415 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1416 * in deep trouble.
1417 * @policy: policy managing CPUs
1418 * @new_freq: CPU frequency the CPU actually runs at
1419 *
1420 * We adjust to current frequency first, and need to clean up later.
1421 * So either call to cpufreq_update_policy() or schedule handle_update()).
1422 */
1423static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1424 unsigned int new_freq)
1425{
1426 struct cpufreq_freqs freqs;
1427
1428 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1429 policy->cur, new_freq);
1430
1431 freqs.old = policy->cur;
1432 freqs.new = new_freq;
1433
1434 cpufreq_freq_transition_begin(policy, &freqs);
1435 cpufreq_freq_transition_end(policy, &freqs, 0);
1436}
1437
1438/**
1439 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1440 * @cpu: CPU number
1441 *
1442 * This is the last known freq, without actually getting it from the driver.
1443 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1444 */
1445unsigned int cpufreq_quick_get(unsigned int cpu)
1446{
1447 struct cpufreq_policy *policy;
1448 unsigned int ret_freq = 0;
1449 unsigned long flags;
1450
1451 read_lock_irqsave(&cpufreq_driver_lock, flags);
1452
1453 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1454 ret_freq = cpufreq_driver->get(cpu);
1455 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1456 return ret_freq;
1457 }
1458
1459 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1460
1461 policy = cpufreq_cpu_get(cpu);
1462 if (policy) {
1463 ret_freq = policy->cur;
1464 cpufreq_cpu_put(policy);
1465 }
1466
1467 return ret_freq;
1468}
1469EXPORT_SYMBOL(cpufreq_quick_get);
1470
1471/**
1472 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1473 * @cpu: CPU number
1474 *
1475 * Just return the max possible frequency for a given CPU.
1476 */
1477unsigned int cpufreq_quick_get_max(unsigned int cpu)
1478{
1479 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1480 unsigned int ret_freq = 0;
1481
1482 if (policy) {
1483 ret_freq = policy->max;
1484 cpufreq_cpu_put(policy);
1485 }
1486
1487 return ret_freq;
1488}
1489EXPORT_SYMBOL(cpufreq_quick_get_max);
1490
1491static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1492{
1493 unsigned int ret_freq = 0;
1494
1495 if (!cpufreq_driver->get)
1496 return ret_freq;
1497
1498 ret_freq = cpufreq_driver->get(policy->cpu);
1499
1500 /*
1501 * Updating inactive policies is invalid, so avoid doing that. Also
1502 * if fast frequency switching is used with the given policy, the check
1503 * against policy->cur is pointless, so skip it in that case too.
1504 */
1505 if (unlikely(policy_is_inactive(policy)) || policy->fast_switch_enabled)
1506 return ret_freq;
1507
1508 if (ret_freq && policy->cur &&
1509 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1510 /* verify no discrepancy between actual and
1511 saved value exists */
1512 if (unlikely(ret_freq != policy->cur)) {
1513 cpufreq_out_of_sync(policy, ret_freq);
1514 schedule_work(&policy->update);
1515 }
1516 }
1517
1518 return ret_freq;
1519}
1520
1521/**
1522 * cpufreq_get - get the current CPU frequency (in kHz)
1523 * @cpu: CPU number
1524 *
1525 * Get the CPU current (static) CPU frequency
1526 */
1527unsigned int cpufreq_get(unsigned int cpu)
1528{
1529 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1530 unsigned int ret_freq = 0;
1531
1532 if (policy) {
1533 down_read(&policy->rwsem);
1534
1535 if (!policy_is_inactive(policy))
1536 ret_freq = __cpufreq_get(policy);
1537
1538 up_read(&policy->rwsem);
1539
1540 cpufreq_cpu_put(policy);
1541 }
1542
1543 return ret_freq;
1544}
1545EXPORT_SYMBOL(cpufreq_get);
1546
1547static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1548{
1549 unsigned int new_freq;
1550
1551 new_freq = cpufreq_driver->get(policy->cpu);
1552 if (!new_freq)
1553 return 0;
1554
1555 if (!policy->cur) {
1556 pr_debug("cpufreq: Driver did not initialize current freq\n");
1557 policy->cur = new_freq;
1558 } else if (policy->cur != new_freq && has_target()) {
1559 cpufreq_out_of_sync(policy, new_freq);
1560 }
1561
1562 return new_freq;
1563}
1564
1565static struct subsys_interface cpufreq_interface = {
1566 .name = "cpufreq",
1567 .subsys = &cpu_subsys,
1568 .add_dev = cpufreq_add_dev,
1569 .remove_dev = cpufreq_remove_dev,
1570};
1571
1572/*
1573 * In case platform wants some specific frequency to be configured
1574 * during suspend..
1575 */
1576int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1577{
1578 int ret;
1579
1580 if (!policy->suspend_freq) {
1581 pr_debug("%s: suspend_freq not defined\n", __func__);
1582 return 0;
1583 }
1584
1585 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1586 policy->suspend_freq);
1587
1588 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1589 CPUFREQ_RELATION_H);
1590 if (ret)
1591 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1592 __func__, policy->suspend_freq, ret);
1593
1594 return ret;
1595}
1596EXPORT_SYMBOL(cpufreq_generic_suspend);
1597
1598/**
1599 * cpufreq_suspend() - Suspend CPUFreq governors
1600 *
1601 * Called during system wide Suspend/Hibernate cycles for suspending governors
1602 * as some platforms can't change frequency after this point in suspend cycle.
1603 * Because some of the devices (like: i2c, regulators, etc) they use for
1604 * changing frequency are suspended quickly after this point.
1605 */
1606void cpufreq_suspend(void)
1607{
1608 struct cpufreq_policy *policy;
1609
1610 if (!cpufreq_driver)
1611 return;
1612
1613 if (!has_target() && !cpufreq_driver->suspend)
1614 goto suspend;
1615
1616 pr_debug("%s: Suspending Governors\n", __func__);
1617
1618 for_each_active_policy(policy) {
1619 if (has_target()) {
1620 down_write(&policy->rwsem);
1621 cpufreq_stop_governor(policy);
1622 up_write(&policy->rwsem);
1623 }
1624
1625 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1626 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1627 policy);
1628 }
1629
1630suspend:
1631 cpufreq_suspended = true;
1632}
1633
1634/**
1635 * cpufreq_resume() - Resume CPUFreq governors
1636 *
1637 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1638 * are suspended with cpufreq_suspend().
1639 */
1640void cpufreq_resume(void)
1641{
1642 struct cpufreq_policy *policy;
1643 int ret;
1644
1645 if (!cpufreq_driver)
1646 return;
1647
1648 cpufreq_suspended = false;
1649
1650 if (!has_target() && !cpufreq_driver->resume)
1651 return;
1652
1653 pr_debug("%s: Resuming Governors\n", __func__);
1654
1655 for_each_active_policy(policy) {
1656 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1657 pr_err("%s: Failed to resume driver: %p\n", __func__,
1658 policy);
1659 } else if (has_target()) {
1660 down_write(&policy->rwsem);
1661 ret = cpufreq_start_governor(policy);
1662 up_write(&policy->rwsem);
1663
1664 if (ret)
1665 pr_err("%s: Failed to start governor for policy: %p\n",
1666 __func__, policy);
1667 }
1668 }
1669}
1670
1671/**
1672 * cpufreq_get_current_driver - return current driver's name
1673 *
1674 * Return the name string of the currently loaded cpufreq driver
1675 * or NULL, if none.
1676 */
1677const char *cpufreq_get_current_driver(void)
1678{
1679 if (cpufreq_driver)
1680 return cpufreq_driver->name;
1681
1682 return NULL;
1683}
1684EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1685
1686/**
1687 * cpufreq_get_driver_data - return current driver data
1688 *
1689 * Return the private data of the currently loaded cpufreq
1690 * driver, or NULL if no cpufreq driver is loaded.
1691 */
1692void *cpufreq_get_driver_data(void)
1693{
1694 if (cpufreq_driver)
1695 return cpufreq_driver->driver_data;
1696
1697 return NULL;
1698}
1699EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1700
1701/*********************************************************************
1702 * NOTIFIER LISTS INTERFACE *
1703 *********************************************************************/
1704
1705/**
1706 * cpufreq_register_notifier - register a driver with cpufreq
1707 * @nb: notifier function to register
1708 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1709 *
1710 * Add a driver to one of two lists: either a list of drivers that
1711 * are notified about clock rate changes (once before and once after
1712 * the transition), or a list of drivers that are notified about
1713 * changes in cpufreq policy.
1714 *
1715 * This function may sleep, and has the same return conditions as
1716 * blocking_notifier_chain_register.
1717 */
1718int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1719{
1720 int ret;
1721
1722 if (cpufreq_disabled())
1723 return -EINVAL;
1724
1725 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1726
1727 switch (list) {
1728 case CPUFREQ_TRANSITION_NOTIFIER:
1729 mutex_lock(&cpufreq_fast_switch_lock);
1730
1731 if (cpufreq_fast_switch_count > 0) {
1732 mutex_unlock(&cpufreq_fast_switch_lock);
1733 return -EBUSY;
1734 }
1735 ret = srcu_notifier_chain_register(
1736 &cpufreq_transition_notifier_list, nb);
1737 if (!ret)
1738 cpufreq_fast_switch_count--;
1739
1740 mutex_unlock(&cpufreq_fast_switch_lock);
1741 break;
1742 case CPUFREQ_POLICY_NOTIFIER:
1743 ret = blocking_notifier_chain_register(
1744 &cpufreq_policy_notifier_list, nb);
1745 break;
1746 default:
1747 ret = -EINVAL;
1748 }
1749
1750 return ret;
1751}
1752EXPORT_SYMBOL(cpufreq_register_notifier);
1753
1754/**
1755 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1756 * @nb: notifier block to be unregistered
1757 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1758 *
1759 * Remove a driver from the CPU frequency notifier list.
1760 *
1761 * This function may sleep, and has the same return conditions as
1762 * blocking_notifier_chain_unregister.
1763 */
1764int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1765{
1766 int ret;
1767
1768 if (cpufreq_disabled())
1769 return -EINVAL;
1770
1771 switch (list) {
1772 case CPUFREQ_TRANSITION_NOTIFIER:
1773 mutex_lock(&cpufreq_fast_switch_lock);
1774
1775 ret = srcu_notifier_chain_unregister(
1776 &cpufreq_transition_notifier_list, nb);
1777 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1778 cpufreq_fast_switch_count++;
1779
1780 mutex_unlock(&cpufreq_fast_switch_lock);
1781 break;
1782 case CPUFREQ_POLICY_NOTIFIER:
1783 ret = blocking_notifier_chain_unregister(
1784 &cpufreq_policy_notifier_list, nb);
1785 break;
1786 default:
1787 ret = -EINVAL;
1788 }
1789
1790 return ret;
1791}
1792EXPORT_SYMBOL(cpufreq_unregister_notifier);
1793
1794
1795/*********************************************************************
1796 * GOVERNORS *
1797 *********************************************************************/
1798
1799/**
1800 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1801 * @policy: cpufreq policy to switch the frequency for.
1802 * @target_freq: New frequency to set (may be approximate).
1803 *
1804 * Carry out a fast frequency switch without sleeping.
1805 *
1806 * The driver's ->fast_switch() callback invoked by this function must be
1807 * suitable for being called from within RCU-sched read-side critical sections
1808 * and it is expected to select the minimum available frequency greater than or
1809 * equal to @target_freq (CPUFREQ_RELATION_L).
1810 *
1811 * This function must not be called if policy->fast_switch_enabled is unset.
1812 *
1813 * Governors calling this function must guarantee that it will never be invoked
1814 * twice in parallel for the same policy and that it will never be called in
1815 * parallel with either ->target() or ->target_index() for the same policy.
1816 *
1817 * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()
1818 * callback to indicate an error condition, the hardware configuration must be
1819 * preserved.
1820 */
1821unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1822 unsigned int target_freq)
1823{
1824 target_freq = clamp_val(target_freq, policy->min, policy->max);
1825
1826 return cpufreq_driver->fast_switch(policy, target_freq);
1827}
1828EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1829
1830/* Must set freqs->new to intermediate frequency */
1831static int __target_intermediate(struct cpufreq_policy *policy,
1832 struct cpufreq_freqs *freqs, int index)
1833{
1834 int ret;
1835
1836 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1837
1838 /* We don't need to switch to intermediate freq */
1839 if (!freqs->new)
1840 return 0;
1841
1842 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1843 __func__, policy->cpu, freqs->old, freqs->new);
1844
1845 cpufreq_freq_transition_begin(policy, freqs);
1846 ret = cpufreq_driver->target_intermediate(policy, index);
1847 cpufreq_freq_transition_end(policy, freqs, ret);
1848
1849 if (ret)
1850 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1851 __func__, ret);
1852
1853 return ret;
1854}
1855
1856static int __target_index(struct cpufreq_policy *policy, int index)
1857{
1858 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1859 unsigned int intermediate_freq = 0;
1860 unsigned int newfreq = policy->freq_table[index].frequency;
1861 int retval = -EINVAL;
1862 bool notify;
1863
1864 if (newfreq == policy->cur)
1865 return 0;
1866
1867 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1868 if (notify) {
1869 /* Handle switching to intermediate frequency */
1870 if (cpufreq_driver->get_intermediate) {
1871 retval = __target_intermediate(policy, &freqs, index);
1872 if (retval)
1873 return retval;
1874
1875 intermediate_freq = freqs.new;
1876 /* Set old freq to intermediate */
1877 if (intermediate_freq)
1878 freqs.old = freqs.new;
1879 }
1880
1881 freqs.new = newfreq;
1882 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1883 __func__, policy->cpu, freqs.old, freqs.new);
1884
1885 cpufreq_freq_transition_begin(policy, &freqs);
1886 }
1887
1888 retval = cpufreq_driver->target_index(policy, index);
1889 if (retval)
1890 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1891 retval);
1892
1893 if (notify) {
1894 cpufreq_freq_transition_end(policy, &freqs, retval);
1895
1896 /*
1897 * Failed after setting to intermediate freq? Driver should have
1898 * reverted back to initial frequency and so should we. Check
1899 * here for intermediate_freq instead of get_intermediate, in
1900 * case we haven't switched to intermediate freq at all.
1901 */
1902 if (unlikely(retval && intermediate_freq)) {
1903 freqs.old = intermediate_freq;
1904 freqs.new = policy->restore_freq;
1905 cpufreq_freq_transition_begin(policy, &freqs);
1906 cpufreq_freq_transition_end(policy, &freqs, 0);
1907 }
1908 }
1909
1910 return retval;
1911}
1912
1913int __cpufreq_driver_target(struct cpufreq_policy *policy,
1914 unsigned int target_freq,
1915 unsigned int relation)
1916{
1917 unsigned int old_target_freq = target_freq;
1918 int index;
1919
1920 if (cpufreq_disabled())
1921 return -ENODEV;
1922
1923 /* Make sure that target_freq is within supported range */
1924 target_freq = clamp_val(target_freq, policy->min, policy->max);
1925
1926 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1927 policy->cpu, target_freq, relation, old_target_freq);
1928
1929 /*
1930 * This might look like a redundant call as we are checking it again
1931 * after finding index. But it is left intentionally for cases where
1932 * exactly same freq is called again and so we can save on few function
1933 * calls.
1934 */
1935 if (target_freq == policy->cur)
1936 return 0;
1937
1938 /* Save last value to restore later on errors */
1939 policy->restore_freq = policy->cur;
1940
1941 if (cpufreq_driver->target)
1942 return cpufreq_driver->target(policy, target_freq, relation);
1943
1944 if (!cpufreq_driver->target_index)
1945 return -EINVAL;
1946
1947 index = cpufreq_frequency_table_target(policy, target_freq, relation);
1948
1949 return __target_index(policy, index);
1950}
1951EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1952
1953int cpufreq_driver_target(struct cpufreq_policy *policy,
1954 unsigned int target_freq,
1955 unsigned int relation)
1956{
1957 int ret = -EINVAL;
1958
1959 down_write(&policy->rwsem);
1960
1961 ret = __cpufreq_driver_target(policy, target_freq, relation);
1962
1963 up_write(&policy->rwsem);
1964
1965 return ret;
1966}
1967EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1968
1969__weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1970{
1971 return NULL;
1972}
1973
1974static int cpufreq_init_governor(struct cpufreq_policy *policy)
1975{
1976 int ret;
1977
1978 /* Don't start any governor operations if we are entering suspend */
1979 if (cpufreq_suspended)
1980 return 0;
1981 /*
1982 * Governor might not be initiated here if ACPI _PPC changed
1983 * notification happened, so check it.
1984 */
1985 if (!policy->governor)
1986 return -EINVAL;
1987
1988 if (policy->governor->max_transition_latency &&
1989 policy->cpuinfo.transition_latency >
1990 policy->governor->max_transition_latency) {
1991 struct cpufreq_governor *gov = cpufreq_fallback_governor();
1992
1993 if (gov) {
1994 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1995 policy->governor->name, gov->name);
1996 policy->governor = gov;
1997 } else {
1998 return -EINVAL;
1999 }
2000 }
2001
2002 if (!try_module_get(policy->governor->owner))
2003 return -EINVAL;
2004
2005 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2006
2007 if (policy->governor->init) {
2008 ret = policy->governor->init(policy);
2009 if (ret) {
2010 module_put(policy->governor->owner);
2011 return ret;
2012 }
2013 }
2014
2015 return 0;
2016}
2017
2018static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2019{
2020 if (cpufreq_suspended || !policy->governor)
2021 return;
2022
2023 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2024
2025 if (policy->governor->exit)
2026 policy->governor->exit(policy);
2027
2028 module_put(policy->governor->owner);
2029}
2030
2031static int cpufreq_start_governor(struct cpufreq_policy *policy)
2032{
2033 int ret;
2034
2035 if (cpufreq_suspended)
2036 return 0;
2037
2038 if (!policy->governor)
2039 return -EINVAL;
2040
2041 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2042
2043 if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2044 cpufreq_update_current_freq(policy);
2045
2046 if (policy->governor->start) {
2047 ret = policy->governor->start(policy);
2048 if (ret)
2049 return ret;
2050 }
2051
2052 if (policy->governor->limits)
2053 policy->governor->limits(policy);
2054
2055 return 0;
2056}
2057
2058static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2059{
2060 if (cpufreq_suspended || !policy->governor)
2061 return;
2062
2063 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2064
2065 if (policy->governor->stop)
2066 policy->governor->stop(policy);
2067}
2068
2069static void cpufreq_governor_limits(struct cpufreq_policy *policy)
2070{
2071 if (cpufreq_suspended || !policy->governor)
2072 return;
2073
2074 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2075
2076 if (policy->governor->limits)
2077 policy->governor->limits(policy);
2078}
2079
2080int cpufreq_register_governor(struct cpufreq_governor *governor)
2081{
2082 int err;
2083
2084 if (!governor)
2085 return -EINVAL;
2086
2087 if (cpufreq_disabled())
2088 return -ENODEV;
2089
2090 mutex_lock(&cpufreq_governor_mutex);
2091
2092 err = -EBUSY;
2093 if (!find_governor(governor->name)) {
2094 err = 0;
2095 list_add(&governor->governor_list, &cpufreq_governor_list);
2096 }
2097
2098 mutex_unlock(&cpufreq_governor_mutex);
2099 return err;
2100}
2101EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2102
2103void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2104{
2105 struct cpufreq_policy *policy;
2106 unsigned long flags;
2107
2108 if (!governor)
2109 return;
2110
2111 if (cpufreq_disabled())
2112 return;
2113
2114 /* clear last_governor for all inactive policies */
2115 read_lock_irqsave(&cpufreq_driver_lock, flags);
2116 for_each_inactive_policy(policy) {
2117 if (!strcmp(policy->last_governor, governor->name)) {
2118 policy->governor = NULL;
2119 strcpy(policy->last_governor, "\0");
2120 }
2121 }
2122 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2123
2124 mutex_lock(&cpufreq_governor_mutex);
2125 list_del(&governor->governor_list);
2126 mutex_unlock(&cpufreq_governor_mutex);
2127 return;
2128}
2129EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2130
2131
2132/*********************************************************************
2133 * POLICY INTERFACE *
2134 *********************************************************************/
2135
2136/**
2137 * cpufreq_get_policy - get the current cpufreq_policy
2138 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2139 * is written
2140 *
2141 * Reads the current cpufreq policy.
2142 */
2143int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2144{
2145 struct cpufreq_policy *cpu_policy;
2146 if (!policy)
2147 return -EINVAL;
2148
2149 cpu_policy = cpufreq_cpu_get(cpu);
2150 if (!cpu_policy)
2151 return -EINVAL;
2152
2153 memcpy(policy, cpu_policy, sizeof(*policy));
2154
2155 cpufreq_cpu_put(cpu_policy);
2156 return 0;
2157}
2158EXPORT_SYMBOL(cpufreq_get_policy);
2159
2160/*
2161 * policy : current policy.
2162 * new_policy: policy to be set.
2163 */
2164static int cpufreq_set_policy(struct cpufreq_policy *policy,
2165 struct cpufreq_policy *new_policy)
2166{
2167 struct cpufreq_governor *old_gov;
2168 int ret;
2169
2170 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2171 new_policy->cpu, new_policy->min, new_policy->max);
2172
2173 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2174
2175 /*
2176 * This check works well when we store new min/max freq attributes,
2177 * because new_policy is a copy of policy with one field updated.
2178 */
2179 if (new_policy->min > new_policy->max)
2180 return -EINVAL;
2181
2182 /* verify the cpu speed can be set within this limit */
2183 ret = cpufreq_driver->verify(new_policy);
2184 if (ret)
2185 return ret;
2186
2187 /* adjust if necessary - all reasons */
2188 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2189 CPUFREQ_ADJUST, new_policy);
2190
2191 /*
2192 * verify the cpu speed can be set within this limit, which might be
2193 * different to the first one
2194 */
2195 ret = cpufreq_driver->verify(new_policy);
2196 if (ret)
2197 return ret;
2198
2199 /* notification of the new policy */
2200 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2201 CPUFREQ_NOTIFY, new_policy);
2202
2203 policy->min = new_policy->min;
2204 policy->max = new_policy->max;
2205
2206 policy->cached_target_freq = UINT_MAX;
2207
2208 pr_debug("new min and max freqs are %u - %u kHz\n",
2209 policy->min, policy->max);
2210
2211 if (cpufreq_driver->setpolicy) {
2212 policy->policy = new_policy->policy;
2213 pr_debug("setting range\n");
2214 return cpufreq_driver->setpolicy(new_policy);
2215 }
2216
2217 if (new_policy->governor == policy->governor) {
2218 pr_debug("cpufreq: governor limits update\n");
2219 cpufreq_governor_limits(policy);
2220 return 0;
2221 }
2222
2223 pr_debug("governor switch\n");
2224
2225 /* save old, working values */
2226 old_gov = policy->governor;
2227 /* end old governor */
2228 if (old_gov) {
2229 cpufreq_stop_governor(policy);
2230 cpufreq_exit_governor(policy);
2231 }
2232
2233 /* start new governor */
2234 policy->governor = new_policy->governor;
2235 ret = cpufreq_init_governor(policy);
2236 if (!ret) {
2237 ret = cpufreq_start_governor(policy);
2238 if (!ret) {
2239 pr_debug("cpufreq: governor change\n");
2240 return 0;
2241 }
2242 cpufreq_exit_governor(policy);
2243 }
2244
2245 /* new governor failed, so re-start old one */
2246 pr_debug("starting governor %s failed\n", policy->governor->name);
2247 if (old_gov) {
2248 policy->governor = old_gov;
2249 if (cpufreq_init_governor(policy))
2250 policy->governor = NULL;
2251 else
2252 cpufreq_start_governor(policy);
2253 }
2254
2255 return ret;
2256}
2257
2258/**
2259 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2260 * @cpu: CPU which shall be re-evaluated
2261 *
2262 * Useful for policy notifiers which have different necessities
2263 * at different times.
2264 */
2265void cpufreq_update_policy(unsigned int cpu)
2266{
2267 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2268 struct cpufreq_policy new_policy;
2269
2270 if (!policy)
2271 return;
2272
2273 down_write(&policy->rwsem);
2274
2275 if (policy_is_inactive(policy))
2276 goto unlock;
2277
2278 pr_debug("updating policy for CPU %u\n", cpu);
2279 memcpy(&new_policy, policy, sizeof(*policy));
2280 new_policy.min = policy->user_policy.min;
2281 new_policy.max = policy->user_policy.max;
2282
2283 /*
2284 * BIOS might change freq behind our back
2285 * -> ask driver for current freq and notify governors about a change
2286 */
2287 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2288 if (cpufreq_suspended)
2289 goto unlock;
2290
2291 new_policy.cur = cpufreq_update_current_freq(policy);
2292 if (WARN_ON(!new_policy.cur))
2293 goto unlock;
2294 }
2295
2296 cpufreq_set_policy(policy, &new_policy);
2297
2298unlock:
2299 up_write(&policy->rwsem);
2300
2301 cpufreq_cpu_put(policy);
2302}
2303EXPORT_SYMBOL(cpufreq_update_policy);
2304
2305/*********************************************************************
2306 * BOOST *
2307 *********************************************************************/
2308static int cpufreq_boost_set_sw(int state)
2309{
2310 struct cpufreq_policy *policy;
2311 int ret = -EINVAL;
2312
2313 for_each_active_policy(policy) {
2314 if (!policy->freq_table)
2315 continue;
2316
2317 ret = cpufreq_frequency_table_cpuinfo(policy,
2318 policy->freq_table);
2319 if (ret) {
2320 pr_err("%s: Policy frequency update failed\n",
2321 __func__);
2322 break;
2323 }
2324
2325 down_write(&policy->rwsem);
2326 policy->user_policy.max = policy->max;
2327 cpufreq_governor_limits(policy);
2328 up_write(&policy->rwsem);
2329 }
2330
2331 return ret;
2332}
2333
2334int cpufreq_boost_trigger_state(int state)
2335{
2336 unsigned long flags;
2337 int ret = 0;
2338
2339 if (cpufreq_driver->boost_enabled == state)
2340 return 0;
2341
2342 write_lock_irqsave(&cpufreq_driver_lock, flags);
2343 cpufreq_driver->boost_enabled = state;
2344 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2345
2346 ret = cpufreq_driver->set_boost(state);
2347 if (ret) {
2348 write_lock_irqsave(&cpufreq_driver_lock, flags);
2349 cpufreq_driver->boost_enabled = !state;
2350 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2351
2352 pr_err("%s: Cannot %s BOOST\n",
2353 __func__, state ? "enable" : "disable");
2354 }
2355
2356 return ret;
2357}
2358
2359static bool cpufreq_boost_supported(void)
2360{
2361 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2362}
2363
2364static int create_boost_sysfs_file(void)
2365{
2366 int ret;
2367
2368 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2369 if (ret)
2370 pr_err("%s: cannot register global BOOST sysfs file\n",
2371 __func__);
2372
2373 return ret;
2374}
2375
2376static void remove_boost_sysfs_file(void)
2377{
2378 if (cpufreq_boost_supported())
2379 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2380}
2381
2382int cpufreq_enable_boost_support(void)
2383{
2384 if (!cpufreq_driver)
2385 return -EINVAL;
2386
2387 if (cpufreq_boost_supported())
2388 return 0;
2389
2390 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2391
2392 /* This will get removed on driver unregister */
2393 return create_boost_sysfs_file();
2394}
2395EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2396
2397int cpufreq_boost_enabled(void)
2398{
2399 return cpufreq_driver->boost_enabled;
2400}
2401EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2402
2403/*********************************************************************
2404 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2405 *********************************************************************/
2406static enum cpuhp_state hp_online;
2407
2408/**
2409 * cpufreq_register_driver - register a CPU Frequency driver
2410 * @driver_data: A struct cpufreq_driver containing the values#
2411 * submitted by the CPU Frequency driver.
2412 *
2413 * Registers a CPU Frequency driver to this core code. This code
2414 * returns zero on success, -EEXIST when another driver got here first
2415 * (and isn't unregistered in the meantime).
2416 *
2417 */
2418int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2419{
2420 unsigned long flags;
2421 int ret;
2422
2423 if (cpufreq_disabled())
2424 return -ENODEV;
2425
2426 if (!driver_data || !driver_data->verify || !driver_data->init ||
2427 !(driver_data->setpolicy || driver_data->target_index ||
2428 driver_data->target) ||
2429 (driver_data->setpolicy && (driver_data->target_index ||
2430 driver_data->target)) ||
2431 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2432 return -EINVAL;
2433
2434 pr_debug("trying to register driver %s\n", driver_data->name);
2435
2436 /* Protect against concurrent CPU online/offline. */
2437 get_online_cpus();
2438
2439 write_lock_irqsave(&cpufreq_driver_lock, flags);
2440 if (cpufreq_driver) {
2441 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2442 ret = -EEXIST;
2443 goto out;
2444 }
2445 cpufreq_driver = driver_data;
2446 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2447
2448 if (driver_data->setpolicy)
2449 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2450
2451 if (cpufreq_boost_supported()) {
2452 ret = create_boost_sysfs_file();
2453 if (ret)
2454 goto err_null_driver;
2455 }
2456
2457 ret = subsys_interface_register(&cpufreq_interface);
2458 if (ret)
2459 goto err_boost_unreg;
2460
2461 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2462 list_empty(&cpufreq_policy_list)) {
2463 /* if all ->init() calls failed, unregister */
2464 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2465 driver_data->name);
2466 goto err_if_unreg;
2467 }
2468
2469 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online",
2470 cpufreq_online,
2471 cpufreq_offline);
2472 if (ret < 0)
2473 goto err_if_unreg;
2474 hp_online = ret;
2475 ret = 0;
2476
2477 pr_debug("driver %s up and running\n", driver_data->name);
2478 goto out;
2479
2480err_if_unreg:
2481 subsys_interface_unregister(&cpufreq_interface);
2482err_boost_unreg:
2483 remove_boost_sysfs_file();
2484err_null_driver:
2485 write_lock_irqsave(&cpufreq_driver_lock, flags);
2486 cpufreq_driver = NULL;
2487 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2488out:
2489 put_online_cpus();
2490 return ret;
2491}
2492EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2493
2494/**
2495 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2496 *
2497 * Unregister the current CPUFreq driver. Only call this if you have
2498 * the right to do so, i.e. if you have succeeded in initialising before!
2499 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2500 * currently not initialised.
2501 */
2502int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2503{
2504 unsigned long flags;
2505
2506 if (!cpufreq_driver || (driver != cpufreq_driver))
2507 return -EINVAL;
2508
2509 pr_debug("unregistering driver %s\n", driver->name);
2510
2511 /* Protect against concurrent cpu hotplug */
2512 get_online_cpus();
2513 subsys_interface_unregister(&cpufreq_interface);
2514 remove_boost_sysfs_file();
2515 cpuhp_remove_state_nocalls(hp_online);
2516
2517 write_lock_irqsave(&cpufreq_driver_lock, flags);
2518
2519 cpufreq_driver = NULL;
2520
2521 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2522 put_online_cpus();
2523
2524 return 0;
2525}
2526EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2527
2528/*
2529 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2530 * or mutexes when secondary CPUs are halted.
2531 */
2532static struct syscore_ops cpufreq_syscore_ops = {
2533 .shutdown = cpufreq_suspend,
2534};
2535
2536struct kobject *cpufreq_global_kobject;
2537EXPORT_SYMBOL(cpufreq_global_kobject);
2538
2539static int __init cpufreq_core_init(void)
2540{
2541 if (cpufreq_disabled())
2542 return -ENODEV;
2543
2544 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2545 BUG_ON(!cpufreq_global_kobject);
2546
2547 register_syscore_ops(&cpufreq_syscore_ops);
2548
2549 return 0;
2550}
2551core_initcall(cpufreq_core_init);