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