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mm: vma_adjust: remove superfluous check for next not NULL
[linux/fpc-iii.git] / drivers / cpufreq / cpufreq.c
blob6e6c1fb60fbc779157a3741334a8cef591a5a14f
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
34 static LIST_HEAD(cpufreq_policy_list);
35
36 static 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 */
55 static 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 */
64 static struct cpufreq_driver *cpufreq_driver;
65 static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
66 static DEFINE_RWLOCK(cpufreq_driver_lock);
67
68 /* Flag to suspend/resume CPUFreq governors */
69 static bool cpufreq_suspended;
70
71 static inline bool has_target(void)
72 {
73 return cpufreq_driver->target_index || cpufreq_driver->target;
74 }
75
76 /* internal prototypes */
77 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
78 static int cpufreq_init_governor(struct cpufreq_policy *policy);
79 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
80 static int cpufreq_start_governor(struct cpufreq_policy *policy);
81 static void cpufreq_stop_governor(struct cpufreq_policy *policy);
82 static 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 */
91 static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
92 static struct srcu_notifier_head cpufreq_transition_notifier_list;
93
94 static bool init_cpufreq_transition_notifier_list_called;
95 static 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 }
101 pure_initcall(init_cpufreq_transition_notifier_list);
102
103 static int off __read_mostly;
104 static int cpufreq_disabled(void)
105 {
106 return off;
107 }
108 void disable_cpufreq(void)
109 {
110 off = 1;
111 }
112 static DEFINE_MUTEX(cpufreq_governor_mutex);
113
114 bool have_governor_per_policy(void)
115 {
116 return !!(cpufreq_driver->flags & CPUFREQ_HAVE_GOVERNOR_PER_POLICY);
117 }
118 EXPORT_SYMBOL_GPL(have_governor_per_policy);
119
120 struct 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 }
127 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
128
129 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
130 {
131 u64 idle_time;
132 u64 cur_wall_time;
133 u64 busy_time;
134
135 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
136
137 busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
138 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
139 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
140 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
141 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
142 busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
143
144 idle_time = cur_wall_time - busy_time;
145 if (wall)
146 *wall = cputime_to_usecs(cur_wall_time);
147
148 return cputime_to_usecs(idle_time);
149 }
150
151 u64 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 }
162 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
163
164 /*
165 * This is a generic cpufreq init() routine which can be used by cpufreq
166 * drivers of SMP systems. It will do following:
167 * - validate & show freq table passed
168 * - set policies transition latency
169 * - policy->cpus with all possible CPUs
170 */
171 int cpufreq_generic_init(struct cpufreq_policy *policy,
172 struct cpufreq_frequency_table *table,
173 unsigned int transition_latency)
174 {
175 int ret;
176
177 ret = cpufreq_table_validate_and_show(policy, table);
178 if (ret) {
179 pr_err("%s: invalid frequency table: %d\n", __func__, ret);
180 return ret;
181 }
182
183 policy->cpuinfo.transition_latency = transition_latency;
184
185 /*
186 * The driver only supports the SMP configuration where all processors
187 * share the clock and voltage and clock.
188 */
189 cpumask_setall(policy->cpus);
190
191 return 0;
192 }
193 EXPORT_SYMBOL_GPL(cpufreq_generic_init);
194
195 struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu)
196 {
197 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
198
199 return policy && cpumask_test_cpu(cpu, policy->cpus) ? policy : NULL;
200 }
201 EXPORT_SYMBOL_GPL(cpufreq_cpu_get_raw);
202
203 unsigned int cpufreq_generic_get(unsigned int cpu)
204 {
205 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
206
207 if (!policy || IS_ERR(policy->clk)) {
208 pr_err("%s: No %s associated to cpu: %d\n",
209 __func__, policy ? "clk" : "policy", cpu);
210 return 0;
211 }
212
213 return clk_get_rate(policy->clk) / 1000;
214 }
215 EXPORT_SYMBOL_GPL(cpufreq_generic_get);
216
217 /**
218 * cpufreq_cpu_get: returns policy for a cpu and marks it busy.
219 *
220 * @cpu: cpu to find policy for.
221 *
222 * This returns policy for 'cpu', returns NULL if it doesn't exist.
223 * It also increments the kobject reference count to mark it busy and so would
224 * require a corresponding call to cpufreq_cpu_put() to decrement it back.
225 * If corresponding call cpufreq_cpu_put() isn't made, the policy wouldn't be
226 * freed as that depends on the kobj count.
227 *
228 * Return: A valid policy on success, otherwise NULL on failure.
229 */
230 struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
231 {
232 struct cpufreq_policy *policy = NULL;
233 unsigned long flags;
234
235 if (WARN_ON(cpu >= nr_cpu_ids))
236 return NULL;
237
238 /* get the cpufreq driver */
239 read_lock_irqsave(&cpufreq_driver_lock, flags);
240
241 if (cpufreq_driver) {
242 /* get the CPU */
243 policy = cpufreq_cpu_get_raw(cpu);
244 if (policy)
245 kobject_get(&policy->kobj);
246 }
247
248 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
249
250 return policy;
251 }
252 EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
253
254 /**
255 * cpufreq_cpu_put: Decrements the usage count of a policy
256 *
257 * @policy: policy earlier returned by cpufreq_cpu_get().
258 *
259 * This decrements the kobject reference count incremented earlier by calling
260 * cpufreq_cpu_get().
261 */
262 void cpufreq_cpu_put(struct cpufreq_policy *policy)
263 {
264 kobject_put(&policy->kobj);
265 }
266 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
267
268 /*********************************************************************
269 * EXTERNALLY AFFECTING FREQUENCY CHANGES *
270 *********************************************************************/
271
272 /**
273 * adjust_jiffies - adjust the system "loops_per_jiffy"
274 *
275 * This function alters the system "loops_per_jiffy" for the clock
276 * speed change. Note that loops_per_jiffy cannot be updated on SMP
277 * systems as each CPU might be scaled differently. So, use the arch
278 * per-CPU loops_per_jiffy value wherever possible.
279 */
280 static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
281 {
282 #ifndef CONFIG_SMP
283 static unsigned long l_p_j_ref;
284 static unsigned int l_p_j_ref_freq;
285
286 if (ci->flags & CPUFREQ_CONST_LOOPS)
287 return;
288
289 if (!l_p_j_ref_freq) {
290 l_p_j_ref = loops_per_jiffy;
291 l_p_j_ref_freq = ci->old;
292 pr_debug("saving %lu as reference value for loops_per_jiffy; freq is %u kHz\n",
293 l_p_j_ref, l_p_j_ref_freq);
294 }
295 if (val == CPUFREQ_POSTCHANGE && ci->old != ci->new) {
296 loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
297 ci->new);
298 pr_debug("scaling loops_per_jiffy to %lu for frequency %u kHz\n",
299 loops_per_jiffy, ci->new);
300 }
301 #endif
302 }
303
304 static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
305 struct cpufreq_freqs *freqs, unsigned int state)
306 {
307 BUG_ON(irqs_disabled());
308
309 if (cpufreq_disabled())
310 return;
311
312 freqs->flags = cpufreq_driver->flags;
313 pr_debug("notification %u of frequency transition to %u kHz\n",
314 state, freqs->new);
315
316 switch (state) {
317
318 case CPUFREQ_PRECHANGE:
319 /* detect if the driver reported a value as "old frequency"
320 * which is not equal to what the cpufreq core thinks is
321 * "old frequency".
322 */
323 if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
324 if ((policy) && (policy->cpu == freqs->cpu) &&
325 (policy->cur) && (policy->cur != freqs->old)) {
326 pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",
327 freqs->old, policy->cur);
328 freqs->old = policy->cur;
329 }
330 }
331 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
332 CPUFREQ_PRECHANGE, freqs);
333 adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
334 break;
335
336 case CPUFREQ_POSTCHANGE:
337 adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
338 pr_debug("FREQ: %lu - CPU: %lu\n",
339 (unsigned long)freqs->new, (unsigned long)freqs->cpu);
340 trace_cpu_frequency(freqs->new, freqs->cpu);
341 cpufreq_stats_record_transition(policy, freqs->new);
342 srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
343 CPUFREQ_POSTCHANGE, freqs);
344 if (likely(policy) && likely(policy->cpu == freqs->cpu))
345 policy->cur = freqs->new;
346 break;
347 }
348 }
349
350 /**
351 * cpufreq_notify_transition - call notifier chain and adjust_jiffies
352 * on frequency transition.
353 *
354 * This function calls the transition notifiers and the "adjust_jiffies"
355 * function. It is called twice on all CPU frequency changes that have
356 * external effects.
357 */
358 static void cpufreq_notify_transition(struct cpufreq_policy *policy,
359 struct cpufreq_freqs *freqs, unsigned int state)
360 {
361 for_each_cpu(freqs->cpu, policy->cpus)
362 __cpufreq_notify_transition(policy, freqs, state);
363 }
364
365 /* Do post notifications when there are chances that transition has failed */
366 static void cpufreq_notify_post_transition(struct cpufreq_policy *policy,
367 struct cpufreq_freqs *freqs, int transition_failed)
368 {
369 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
370 if (!transition_failed)
371 return;
372
373 swap(freqs->old, freqs->new);
374 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
375 cpufreq_notify_transition(policy, freqs, CPUFREQ_POSTCHANGE);
376 }
377
378 void cpufreq_freq_transition_begin(struct cpufreq_policy *policy,
379 struct cpufreq_freqs *freqs)
380 {
381
382 /*
383 * Catch double invocations of _begin() which lead to self-deadlock.
384 * ASYNC_NOTIFICATION drivers are left out because the cpufreq core
385 * doesn't invoke _begin() on their behalf, and hence the chances of
386 * double invocations are very low. Moreover, there are scenarios
387 * where these checks can emit false-positive warnings in these
388 * drivers; so we avoid that by skipping them altogether.
389 */
390 WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
391 && current == policy->transition_task);
392
393 wait:
394 wait_event(policy->transition_wait, !policy->transition_ongoing);
395
396 spin_lock(&policy->transition_lock);
397
398 if (unlikely(policy->transition_ongoing)) {
399 spin_unlock(&policy->transition_lock);
400 goto wait;
401 }
402
403 policy->transition_ongoing = true;
404 policy->transition_task = current;
405
406 spin_unlock(&policy->transition_lock);
407
408 cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE);
409 }
410 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin);
411
412 void cpufreq_freq_transition_end(struct cpufreq_policy *policy,
413 struct cpufreq_freqs *freqs, int transition_failed)
414 {
415 if (unlikely(WARN_ON(!policy->transition_ongoing)))
416 return;
417
418 cpufreq_notify_post_transition(policy, freqs, transition_failed);
419
420 policy->transition_ongoing = false;
421 policy->transition_task = NULL;
422
423 wake_up(&policy->transition_wait);
424 }
425 EXPORT_SYMBOL_GPL(cpufreq_freq_transition_end);
426
427 /*
428 * Fast frequency switching status count. Positive means "enabled", negative
429 * means "disabled" and 0 means "not decided yet".
430 */
431 static int cpufreq_fast_switch_count;
432 static DEFINE_MUTEX(cpufreq_fast_switch_lock);
433
434 static void cpufreq_list_transition_notifiers(void)
435 {
436 struct notifier_block *nb;
437
438 pr_info("Registered transition notifiers:\n");
439
440 mutex_lock(&cpufreq_transition_notifier_list.mutex);
441
442 for (nb = cpufreq_transition_notifier_list.head; nb; nb = nb->next)
443 pr_info("%pF\n", nb->notifier_call);
444
445 mutex_unlock(&cpufreq_transition_notifier_list.mutex);
446 }
447
448 /**
449 * cpufreq_enable_fast_switch - Enable fast frequency switching for policy.
450 * @policy: cpufreq policy to enable fast frequency switching for.
451 *
452 * Try to enable fast frequency switching for @policy.
453 *
454 * The attempt will fail if there is at least one transition notifier registered
455 * at this point, as fast frequency switching is quite fundamentally at odds
456 * with transition notifiers. Thus if successful, it will make registration of
457 * transition notifiers fail going forward.
458 */
459 void cpufreq_enable_fast_switch(struct cpufreq_policy *policy)
460 {
461 lockdep_assert_held(&policy->rwsem);
462
463 if (!policy->fast_switch_possible)
464 return;
465
466 mutex_lock(&cpufreq_fast_switch_lock);
467 if (cpufreq_fast_switch_count >= 0) {
468 cpufreq_fast_switch_count++;
469 policy->fast_switch_enabled = true;
470 } else {
471 pr_warn("CPU%u: Fast frequency switching not enabled\n",
472 policy->cpu);
473 cpufreq_list_transition_notifiers();
474 }
475 mutex_unlock(&cpufreq_fast_switch_lock);
476 }
477 EXPORT_SYMBOL_GPL(cpufreq_enable_fast_switch);
478
479 /**
480 * cpufreq_disable_fast_switch - Disable fast frequency switching for policy.
481 * @policy: cpufreq policy to disable fast frequency switching for.
482 */
483 void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
484 {
485 mutex_lock(&cpufreq_fast_switch_lock);
486 if (policy->fast_switch_enabled) {
487 policy->fast_switch_enabled = false;
488 if (!WARN_ON(cpufreq_fast_switch_count <= 0))
489 cpufreq_fast_switch_count--;
490 }
491 mutex_unlock(&cpufreq_fast_switch_lock);
492 }
493 EXPORT_SYMBOL_GPL(cpufreq_disable_fast_switch);
494
495 /**
496 * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
497 * one.
498 * @target_freq: target frequency to resolve.
499 *
500 * The target to driver frequency mapping is cached in the policy.
501 *
502 * Return: Lowest driver-supported frequency greater than or equal to the
503 * given target_freq, subject to policy (min/max) and driver limitations.
504 */
505 unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
506 unsigned int target_freq)
507 {
508 target_freq = clamp_val(target_freq, policy->min, policy->max);
509 policy->cached_target_freq = target_freq;
510
511 if (cpufreq_driver->target_index) {
512 int idx;
513
514 idx = cpufreq_frequency_table_target(policy, target_freq,
515 CPUFREQ_RELATION_L);
516 policy->cached_resolved_idx = idx;
517 return policy->freq_table[idx].frequency;
518 }
519
520 if (cpufreq_driver->resolve_freq)
521 return cpufreq_driver->resolve_freq(policy, target_freq);
522
523 return target_freq;
524 }
525 EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq);
526
527 /*********************************************************************
528 * SYSFS INTERFACE *
529 *********************************************************************/
530 static ssize_t show_boost(struct kobject *kobj,
531 struct attribute *attr, char *buf)
532 {
533 return sprintf(buf, "%d\n", cpufreq_driver->boost_enabled);
534 }
535
536 static ssize_t store_boost(struct kobject *kobj, struct attribute *attr,
537 const char *buf, size_t count)
538 {
539 int ret, enable;
540
541 ret = sscanf(buf, "%d", &enable);
542 if (ret != 1 || enable < 0 || enable > 1)
543 return -EINVAL;
544
545 if (cpufreq_boost_trigger_state(enable)) {
546 pr_err("%s: Cannot %s BOOST!\n",
547 __func__, enable ? "enable" : "disable");
548 return -EINVAL;
549 }
550
551 pr_debug("%s: cpufreq BOOST %s\n",
552 __func__, enable ? "enabled" : "disabled");
553
554 return count;
555 }
556 define_one_global_rw(boost);
557
558 static struct cpufreq_governor *find_governor(const char *str_governor)
559 {
560 struct cpufreq_governor *t;
561
562 for_each_governor(t)
563 if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN))
564 return t;
565
566 return NULL;
567 }
568
569 /**
570 * cpufreq_parse_governor - parse a governor string
571 */
572 static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
573 struct cpufreq_governor **governor)
574 {
575 int err = -EINVAL;
576
577 if (cpufreq_driver->setpolicy) {
578 if (!strncasecmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
579 *policy = CPUFREQ_POLICY_PERFORMANCE;
580 err = 0;
581 } else if (!strncasecmp(str_governor, "powersave",
582 CPUFREQ_NAME_LEN)) {
583 *policy = CPUFREQ_POLICY_POWERSAVE;
584 err = 0;
585 }
586 } else {
587 struct cpufreq_governor *t;
588
589 mutex_lock(&cpufreq_governor_mutex);
590
591 t = find_governor(str_governor);
592
593 if (t == NULL) {
594 int ret;
595
596 mutex_unlock(&cpufreq_governor_mutex);
597 ret = request_module("cpufreq_%s", str_governor);
598 mutex_lock(&cpufreq_governor_mutex);
599
600 if (ret == 0)
601 t = find_governor(str_governor);
602 }
603
604 if (t != NULL) {
605 *governor = t;
606 err = 0;
607 }
608
609 mutex_unlock(&cpufreq_governor_mutex);
610 }
611 return err;
612 }
613
614 /**
615 * cpufreq_per_cpu_attr_read() / show_##file_name() -
616 * print out cpufreq information
617 *
618 * Write out information from cpufreq_driver->policy[cpu]; object must be
619 * "unsigned int".
620 */
621
622 #define show_one(file_name, object) \
623 static ssize_t show_##file_name \
624 (struct cpufreq_policy *policy, char *buf) \
625 { \
626 return sprintf(buf, "%u\n", policy->object); \
627 }
628
629 show_one(cpuinfo_min_freq, cpuinfo.min_freq);
630 show_one(cpuinfo_max_freq, cpuinfo.max_freq);
631 show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
632 show_one(scaling_min_freq, min);
633 show_one(scaling_max_freq, max);
634
635 static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
636 {
637 ssize_t ret;
638
639 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
640 ret = sprintf(buf, "%u\n", cpufreq_driver->get(policy->cpu));
641 else
642 ret = sprintf(buf, "%u\n", policy->cur);
643 return ret;
644 }
645
646 static int cpufreq_set_policy(struct cpufreq_policy *policy,
647 struct cpufreq_policy *new_policy);
648
649 /**
650 * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
651 */
652 #define store_one(file_name, object) \
653 static ssize_t store_##file_name \
654 (struct cpufreq_policy *policy, const char *buf, size_t count) \
655 { \
656 int ret, temp; \
657 struct cpufreq_policy new_policy; \
658 \
659 memcpy(&new_policy, policy, sizeof(*policy)); \
660 \
661 ret = sscanf(buf, "%u", &new_policy.object); \
662 if (ret != 1) \
663 return -EINVAL; \
664 \
665 temp = new_policy.object; \
666 ret = cpufreq_set_policy(policy, &new_policy); \
667 if (!ret) \
668 policy->user_policy.object = temp; \
669 \
670 return ret ? ret : count; \
671 }
672
673 store_one(scaling_min_freq, min);
674 store_one(scaling_max_freq, max);
675
676 /**
677 * show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
678 */
679 static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
680 char *buf)
681 {
682 unsigned int cur_freq = __cpufreq_get(policy);
683 if (!cur_freq)
684 return sprintf(buf, "<unknown>");
685 return sprintf(buf, "%u\n", cur_freq);
686 }
687
688 /**
689 * show_scaling_governor - show the current policy for the specified CPU
690 */
691 static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
692 {
693 if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
694 return sprintf(buf, "powersave\n");
695 else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
696 return sprintf(buf, "performance\n");
697 else if (policy->governor)
698 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
699 policy->governor->name);
700 return -EINVAL;
701 }
702
703 /**
704 * store_scaling_governor - store policy for the specified CPU
705 */
706 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
707 const char *buf, size_t count)
708 {
709 int ret;
710 char str_governor[16];
711 struct cpufreq_policy new_policy;
712
713 memcpy(&new_policy, policy, sizeof(*policy));
714
715 ret = sscanf(buf, "%15s", str_governor);
716 if (ret != 1)
717 return -EINVAL;
718
719 if (cpufreq_parse_governor(str_governor, &new_policy.policy,
720 &new_policy.governor))
721 return -EINVAL;
722
723 ret = cpufreq_set_policy(policy, &new_policy);
724 return ret ? ret : count;
725 }
726
727 /**
728 * show_scaling_driver - show the cpufreq driver currently loaded
729 */
730 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
731 {
732 return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
733 }
734
735 /**
736 * show_scaling_available_governors - show the available CPUfreq governors
737 */
738 static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
739 char *buf)
740 {
741 ssize_t i = 0;
742 struct cpufreq_governor *t;
743
744 if (!has_target()) {
745 i += sprintf(buf, "performance powersave");
746 goto out;
747 }
748
749 for_each_governor(t) {
750 if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
751 - (CPUFREQ_NAME_LEN + 2)))
752 goto out;
753 i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
754 }
755 out:
756 i += sprintf(&buf[i], "\n");
757 return i;
758 }
759
760 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
761 {
762 ssize_t i = 0;
763 unsigned int cpu;
764
765 for_each_cpu(cpu, mask) {
766 if (i)
767 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
768 i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
769 if (i >= (PAGE_SIZE - 5))
770 break;
771 }
772 i += sprintf(&buf[i], "\n");
773 return i;
774 }
775 EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
776
777 /**
778 * show_related_cpus - show the CPUs affected by each transition even if
779 * hw coordination is in use
780 */
781 static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
782 {
783 return cpufreq_show_cpus(policy->related_cpus, buf);
784 }
785
786 /**
787 * show_affected_cpus - show the CPUs affected by each transition
788 */
789 static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
790 {
791 return cpufreq_show_cpus(policy->cpus, buf);
792 }
793
794 static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
795 const char *buf, size_t count)
796 {
797 unsigned int freq = 0;
798 unsigned int ret;
799
800 if (!policy->governor || !policy->governor->store_setspeed)
801 return -EINVAL;
802
803 ret = sscanf(buf, "%u", &freq);
804 if (ret != 1)
805 return -EINVAL;
806
807 policy->governor->store_setspeed(policy, freq);
808
809 return count;
810 }
811
812 static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
813 {
814 if (!policy->governor || !policy->governor->show_setspeed)
815 return sprintf(buf, "<unsupported>\n");
816
817 return policy->governor->show_setspeed(policy, buf);
818 }
819
820 /**
821 * show_bios_limit - show the current cpufreq HW/BIOS limitation
822 */
823 static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
824 {
825 unsigned int limit;
826 int ret;
827 if (cpufreq_driver->bios_limit) {
828 ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
829 if (!ret)
830 return sprintf(buf, "%u\n", limit);
831 }
832 return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
833 }
834
835 cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
836 cpufreq_freq_attr_ro(cpuinfo_min_freq);
837 cpufreq_freq_attr_ro(cpuinfo_max_freq);
838 cpufreq_freq_attr_ro(cpuinfo_transition_latency);
839 cpufreq_freq_attr_ro(scaling_available_governors);
840 cpufreq_freq_attr_ro(scaling_driver);
841 cpufreq_freq_attr_ro(scaling_cur_freq);
842 cpufreq_freq_attr_ro(bios_limit);
843 cpufreq_freq_attr_ro(related_cpus);
844 cpufreq_freq_attr_ro(affected_cpus);
845 cpufreq_freq_attr_rw(scaling_min_freq);
846 cpufreq_freq_attr_rw(scaling_max_freq);
847 cpufreq_freq_attr_rw(scaling_governor);
848 cpufreq_freq_attr_rw(scaling_setspeed);
849
850 static struct attribute *default_attrs[] = {
851 &cpuinfo_min_freq.attr,
852 &cpuinfo_max_freq.attr,
853 &cpuinfo_transition_latency.attr,
854 &scaling_min_freq.attr,
855 &scaling_max_freq.attr,
856 &affected_cpus.attr,
857 &related_cpus.attr,
858 &scaling_governor.attr,
859 &scaling_driver.attr,
860 &scaling_available_governors.attr,
861 &scaling_setspeed.attr,
862 NULL
863 };
864
865 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
866 #define to_attr(a) container_of(a, struct freq_attr, attr)
867
868 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
869 {
870 struct cpufreq_policy *policy = to_policy(kobj);
871 struct freq_attr *fattr = to_attr(attr);
872 ssize_t ret;
873
874 down_read(&policy->rwsem);
875 ret = fattr->show(policy, buf);
876 up_read(&policy->rwsem);
877
878 return ret;
879 }
880
881 static ssize_t store(struct kobject *kobj, struct attribute *attr,
882 const char *buf, size_t count)
883 {
884 struct cpufreq_policy *policy = to_policy(kobj);
885 struct freq_attr *fattr = to_attr(attr);
886 ssize_t ret = -EINVAL;
887
888 get_online_cpus();
889
890 if (cpu_online(policy->cpu)) {
891 down_write(&policy->rwsem);
892 ret = fattr->store(policy, buf, count);
893 up_write(&policy->rwsem);
894 }
895
896 put_online_cpus();
897
898 return ret;
899 }
900
901 static void cpufreq_sysfs_release(struct kobject *kobj)
902 {
903 struct cpufreq_policy *policy = to_policy(kobj);
904 pr_debug("last reference is dropped\n");
905 complete(&policy->kobj_unregister);
906 }
907
908 static const struct sysfs_ops sysfs_ops = {
909 .show = show,
910 .store = store,
911 };
912
913 static struct kobj_type ktype_cpufreq = {
914 .sysfs_ops = &sysfs_ops,
915 .default_attrs = default_attrs,
916 .release = cpufreq_sysfs_release,
917 };
918
919 static int add_cpu_dev_symlink(struct cpufreq_policy *policy,
920 struct device *dev)
921 {
922 dev_dbg(dev, "%s: Adding symlink\n", __func__);
923 return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
924 }
925
926 static void remove_cpu_dev_symlink(struct cpufreq_policy *policy,
927 struct device *dev)
928 {
929 dev_dbg(dev, "%s: Removing symlink\n", __func__);
930 sysfs_remove_link(&dev->kobj, "cpufreq");
931 }
932
933 static int cpufreq_add_dev_interface(struct cpufreq_policy *policy)
934 {
935 struct freq_attr **drv_attr;
936 int ret = 0;
937
938 /* set up files for this cpu device */
939 drv_attr = cpufreq_driver->attr;
940 while (drv_attr && *drv_attr) {
941 ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
942 if (ret)
943 return ret;
944 drv_attr++;
945 }
946 if (cpufreq_driver->get) {
947 ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
948 if (ret)
949 return ret;
950 }
951
952 ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
953 if (ret)
954 return ret;
955
956 if (cpufreq_driver->bios_limit) {
957 ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
958 if (ret)
959 return ret;
960 }
961
962 return 0;
963 }
964
965 __weak struct cpufreq_governor *cpufreq_default_governor(void)
966 {
967 return NULL;
968 }
969
970 static int cpufreq_init_policy(struct cpufreq_policy *policy)
971 {
972 struct cpufreq_governor *gov = NULL;
973 struct cpufreq_policy new_policy;
974
975 memcpy(&new_policy, policy, sizeof(*policy));
976
977 /* Update governor of new_policy to the governor used before hotplug */
978 gov = find_governor(policy->last_governor);
979 if (gov) {
980 pr_debug("Restoring governor %s for cpu %d\n",
981 policy->governor->name, policy->cpu);
982 } else {
983 gov = cpufreq_default_governor();
984 if (!gov)
985 return -ENODATA;
986 }
987
988 new_policy.governor = gov;
989
990 /* Use the default policy if there is no last_policy. */
991 if (cpufreq_driver->setpolicy) {
992 if (policy->last_policy)
993 new_policy.policy = policy->last_policy;
994 else
995 cpufreq_parse_governor(gov->name, &new_policy.policy,
996 NULL);
997 }
998 /* set default policy */
999 return cpufreq_set_policy(policy, &new_policy);
1000 }
1001
1002 static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
1003 {
1004 int ret = 0;
1005
1006 /* Has this CPU been taken care of already? */
1007 if (cpumask_test_cpu(cpu, policy->cpus))
1008 return 0;
1009
1010 down_write(&policy->rwsem);
1011 if (has_target())
1012 cpufreq_stop_governor(policy);
1013
1014 cpumask_set_cpu(cpu, policy->cpus);
1015
1016 if (has_target()) {
1017 ret = cpufreq_start_governor(policy);
1018 if (ret)
1019 pr_err("%s: Failed to start governor\n", __func__);
1020 }
1021 up_write(&policy->rwsem);
1022 return ret;
1023 }
1024
1025 static void handle_update(struct work_struct *work)
1026 {
1027 struct cpufreq_policy *policy =
1028 container_of(work, struct cpufreq_policy, update);
1029 unsigned int cpu = policy->cpu;
1030 pr_debug("handle_update for cpu %u called\n", cpu);
1031 cpufreq_update_policy(cpu);
1032 }
1033
1034 static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
1035 {
1036 struct cpufreq_policy *policy;
1037 int ret;
1038
1039 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
1040 if (!policy)
1041 return NULL;
1042
1043 if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
1044 goto err_free_policy;
1045
1046 if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
1047 goto err_free_cpumask;
1048
1049 if (!zalloc_cpumask_var(&policy->real_cpus, GFP_KERNEL))
1050 goto err_free_rcpumask;
1051
1052 ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
1053 cpufreq_global_kobject, "policy%u", cpu);
1054 if (ret) {
1055 pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
1056 goto err_free_real_cpus;
1057 }
1058
1059 INIT_LIST_HEAD(&policy->policy_list);
1060 init_rwsem(&policy->rwsem);
1061 spin_lock_init(&policy->transition_lock);
1062 init_waitqueue_head(&policy->transition_wait);
1063 init_completion(&policy->kobj_unregister);
1064 INIT_WORK(&policy->update, handle_update);
1065
1066 policy->cpu = cpu;
1067 return policy;
1068
1069 err_free_real_cpus:
1070 free_cpumask_var(policy->real_cpus);
1071 err_free_rcpumask:
1072 free_cpumask_var(policy->related_cpus);
1073 err_free_cpumask:
1074 free_cpumask_var(policy->cpus);
1075 err_free_policy:
1076 kfree(policy);
1077
1078 return NULL;
1079 }
1080
1081 static void cpufreq_policy_put_kobj(struct cpufreq_policy *policy, bool notify)
1082 {
1083 struct kobject *kobj;
1084 struct completion *cmp;
1085
1086 if (notify)
1087 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1088 CPUFREQ_REMOVE_POLICY, policy);
1089
1090 down_write(&policy->rwsem);
1091 cpufreq_stats_free_table(policy);
1092 kobj = &policy->kobj;
1093 cmp = &policy->kobj_unregister;
1094 up_write(&policy->rwsem);
1095 kobject_put(kobj);
1096
1097 /*
1098 * We need to make sure that the underlying kobj is
1099 * actually not referenced anymore by anybody before we
1100 * proceed with unloading.
1101 */
1102 pr_debug("waiting for dropping of refcount\n");
1103 wait_for_completion(cmp);
1104 pr_debug("wait complete\n");
1105 }
1106
1107 static void cpufreq_policy_free(struct cpufreq_policy *policy, bool notify)
1108 {
1109 unsigned long flags;
1110 int cpu;
1111
1112 /* Remove policy from list */
1113 write_lock_irqsave(&cpufreq_driver_lock, flags);
1114 list_del(&policy->policy_list);
1115
1116 for_each_cpu(cpu, policy->related_cpus)
1117 per_cpu(cpufreq_cpu_data, cpu) = NULL;
1118 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1119
1120 cpufreq_policy_put_kobj(policy, notify);
1121 free_cpumask_var(policy->real_cpus);
1122 free_cpumask_var(policy->related_cpus);
1123 free_cpumask_var(policy->cpus);
1124 kfree(policy);
1125 }
1126
1127 static int cpufreq_online(unsigned int cpu)
1128 {
1129 struct cpufreq_policy *policy;
1130 bool new_policy;
1131 unsigned long flags;
1132 unsigned int j;
1133 int ret;
1134
1135 pr_debug("%s: bringing CPU%u online\n", __func__, cpu);
1136
1137 /* Check if this CPU already has a policy to manage it */
1138 policy = per_cpu(cpufreq_cpu_data, cpu);
1139 if (policy) {
1140 WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus));
1141 if (!policy_is_inactive(policy))
1142 return cpufreq_add_policy_cpu(policy, cpu);
1143
1144 /* This is the only online CPU for the policy. Start over. */
1145 new_policy = false;
1146 down_write(&policy->rwsem);
1147 policy->cpu = cpu;
1148 policy->governor = NULL;
1149 up_write(&policy->rwsem);
1150 } else {
1151 new_policy = true;
1152 policy = cpufreq_policy_alloc(cpu);
1153 if (!policy)
1154 return -ENOMEM;
1155 }
1156
1157 cpumask_copy(policy->cpus, cpumask_of(cpu));
1158
1159 /* call driver. From then on the cpufreq must be able
1160 * to accept all calls to ->verify and ->setpolicy for this CPU
1161 */
1162 ret = cpufreq_driver->init(policy);
1163 if (ret) {
1164 pr_debug("initialization failed\n");
1165 goto out_free_policy;
1166 }
1167
1168 down_write(&policy->rwsem);
1169
1170 if (new_policy) {
1171 /* related_cpus should at least include policy->cpus. */
1172 cpumask_copy(policy->related_cpus, policy->cpus);
1173 /* Clear mask of registered CPUs */
1174 cpumask_clear(policy->real_cpus);
1175 }
1176
1177 /*
1178 * affected cpus must always be the one, which are online. We aren't
1179 * managing offline cpus here.
1180 */
1181 cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
1182
1183 if (new_policy) {
1184 policy->user_policy.min = policy->min;
1185 policy->user_policy.max = policy->max;
1186
1187 write_lock_irqsave(&cpufreq_driver_lock, flags);
1188 for_each_cpu(j, policy->related_cpus)
1189 per_cpu(cpufreq_cpu_data, j) = policy;
1190 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1191 }
1192
1193 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
1194 policy->cur = cpufreq_driver->get(policy->cpu);
1195 if (!policy->cur) {
1196 pr_err("%s: ->get() failed\n", __func__);
1197 goto out_exit_policy;
1198 }
1199 }
1200
1201 /*
1202 * Sometimes boot loaders set CPU frequency to a value outside of
1203 * frequency table present with cpufreq core. In such cases CPU might be
1204 * unstable if it has to run on that frequency for long duration of time
1205 * and so its better to set it to a frequency which is specified in
1206 * freq-table. This also makes cpufreq stats inconsistent as
1207 * cpufreq-stats would fail to register because current frequency of CPU
1208 * isn't found in freq-table.
1209 *
1210 * Because we don't want this change to effect boot process badly, we go
1211 * for the next freq which is >= policy->cur ('cur' must be set by now,
1212 * otherwise we will end up setting freq to lowest of the table as 'cur'
1213 * is initialized to zero).
1214 *
1215 * We are passing target-freq as "policy->cur - 1" otherwise
1216 * __cpufreq_driver_target() would simply fail, as policy->cur will be
1217 * equal to target-freq.
1218 */
1219 if ((cpufreq_driver->flags & CPUFREQ_NEED_INITIAL_FREQ_CHECK)
1220 && has_target()) {
1221 /* Are we running at unknown frequency ? */
1222 ret = cpufreq_frequency_table_get_index(policy, policy->cur);
1223 if (ret == -EINVAL) {
1224 /* Warn user and fix it */
1225 pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
1226 __func__, policy->cpu, policy->cur);
1227 ret = __cpufreq_driver_target(policy, policy->cur - 1,
1228 CPUFREQ_RELATION_L);
1229
1230 /*
1231 * Reaching here after boot in a few seconds may not
1232 * mean that system will remain stable at "unknown"
1233 * frequency for longer duration. Hence, a BUG_ON().
1234 */
1235 BUG_ON(ret);
1236 pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
1237 __func__, policy->cpu, policy->cur);
1238 }
1239 }
1240
1241 if (new_policy) {
1242 ret = cpufreq_add_dev_interface(policy);
1243 if (ret)
1244 goto out_exit_policy;
1245
1246 cpufreq_stats_create_table(policy);
1247 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1248 CPUFREQ_CREATE_POLICY, policy);
1249
1250 write_lock_irqsave(&cpufreq_driver_lock, flags);
1251 list_add(&policy->policy_list, &cpufreq_policy_list);
1252 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
1253 }
1254
1255 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
1256 CPUFREQ_START, policy);
1257
1258 ret = cpufreq_init_policy(policy);
1259 if (ret) {
1260 pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
1261 __func__, cpu, ret);
1262 /* cpufreq_policy_free() will notify based on this */
1263 new_policy = false;
1264 goto out_exit_policy;
1265 }
1266
1267 up_write(&policy->rwsem);
1268
1269 kobject_uevent(&policy->kobj, KOBJ_ADD);
1270
1271 /* Callback for handling stuff after policy is ready */
1272 if (cpufreq_driver->ready)
1273 cpufreq_driver->ready(policy);
1274
1275 pr_debug("initialization complete\n");
1276
1277 return 0;
1278
1279 out_exit_policy:
1280 up_write(&policy->rwsem);
1281
1282 if (cpufreq_driver->exit)
1283 cpufreq_driver->exit(policy);
1284 out_free_policy:
1285 cpufreq_policy_free(policy, !new_policy);
1286 return ret;
1287 }
1288
1289 static int cpufreq_offline(unsigned int cpu);
1290
1291 /**
1292 * cpufreq_add_dev - the cpufreq interface for a CPU device.
1293 * @dev: CPU device.
1294 * @sif: Subsystem interface structure pointer (not used)
1295 */
1296 static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
1297 {
1298 struct cpufreq_policy *policy;
1299 unsigned cpu = dev->id;
1300 int ret;
1301
1302 dev_dbg(dev, "%s: adding CPU%u\n", __func__, cpu);
1303
1304 if (cpu_online(cpu)) {
1305 ret = cpufreq_online(cpu);
1306 if (ret)
1307 return ret;
1308 }
1309
1310 /* Create sysfs link on CPU registration */
1311 policy = per_cpu(cpufreq_cpu_data, cpu);
1312 if (!policy || cpumask_test_and_set_cpu(cpu, policy->real_cpus))
1313 return 0;
1314
1315 ret = add_cpu_dev_symlink(policy, dev);
1316 if (ret) {
1317 cpumask_clear_cpu(cpu, policy->real_cpus);
1318 cpufreq_offline(cpu);
1319 }
1320
1321 return ret;
1322 }
1323
1324 static int cpufreq_offline(unsigned int cpu)
1325 {
1326 struct cpufreq_policy *policy;
1327 int ret;
1328
1329 pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
1330
1331 policy = cpufreq_cpu_get_raw(cpu);
1332 if (!policy) {
1333 pr_debug("%s: No cpu_data found\n", __func__);
1334 return 0;
1335 }
1336
1337 down_write(&policy->rwsem);
1338 if (has_target())
1339 cpufreq_stop_governor(policy);
1340
1341 cpumask_clear_cpu(cpu, policy->cpus);
1342
1343 if (policy_is_inactive(policy)) {
1344 if (has_target())
1345 strncpy(policy->last_governor, policy->governor->name,
1346 CPUFREQ_NAME_LEN);
1347 else
1348 policy->last_policy = policy->policy;
1349 } else if (cpu == policy->cpu) {
1350 /* Nominate new CPU */
1351 policy->cpu = cpumask_any(policy->cpus);
1352 }
1353
1354 /* Start governor again for active policy */
1355 if (!policy_is_inactive(policy)) {
1356 if (has_target()) {
1357 ret = cpufreq_start_governor(policy);
1358 if (ret)
1359 pr_err("%s: Failed to start governor\n", __func__);
1360 }
1361
1362 goto unlock;
1363 }
1364
1365 if (cpufreq_driver->stop_cpu)
1366 cpufreq_driver->stop_cpu(policy);
1367
1368 if (has_target())
1369 cpufreq_exit_governor(policy);
1370
1371 /*
1372 * Perform the ->exit() even during light-weight tear-down,
1373 * since this is a core component, and is essential for the
1374 * subsequent light-weight ->init() to succeed.
1375 */
1376 if (cpufreq_driver->exit) {
1377 cpufreq_driver->exit(policy);
1378 policy->freq_table = NULL;
1379 }
1380
1381 unlock:
1382 up_write(&policy->rwsem);
1383 return 0;
1384 }
1385
1386 /**
1387 * cpufreq_remove_dev - remove a CPU device
1388 *
1389 * Removes the cpufreq interface for a CPU device.
1390 */
1391 static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
1392 {
1393 unsigned int cpu = dev->id;
1394 struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
1395
1396 if (!policy)
1397 return;
1398
1399 if (cpu_online(cpu))
1400 cpufreq_offline(cpu);
1401
1402 cpumask_clear_cpu(cpu, policy->real_cpus);
1403 remove_cpu_dev_symlink(policy, dev);
1404
1405 if (cpumask_empty(policy->real_cpus))
1406 cpufreq_policy_free(policy, true);
1407 }
1408
1409 /**
1410 * cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
1411 * in deep trouble.
1412 * @policy: policy managing CPUs
1413 * @new_freq: CPU frequency the CPU actually runs at
1414 *
1415 * We adjust to current frequency first, and need to clean up later.
1416 * So either call to cpufreq_update_policy() or schedule handle_update()).
1417 */
1418 static void cpufreq_out_of_sync(struct cpufreq_policy *policy,
1419 unsigned int new_freq)
1420 {
1421 struct cpufreq_freqs freqs;
1422
1423 pr_debug("Warning: CPU frequency out of sync: cpufreq and timing core thinks of %u, is %u kHz\n",
1424 policy->cur, new_freq);
1425
1426 freqs.old = policy->cur;
1427 freqs.new = new_freq;
1428
1429 cpufreq_freq_transition_begin(policy, &freqs);
1430 cpufreq_freq_transition_end(policy, &freqs, 0);
1431 }
1432
1433 /**
1434 * cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
1435 * @cpu: CPU number
1436 *
1437 * This is the last known freq, without actually getting it from the driver.
1438 * Return value will be same as what is shown in scaling_cur_freq in sysfs.
1439 */
1440 unsigned int cpufreq_quick_get(unsigned int cpu)
1441 {
1442 struct cpufreq_policy *policy;
1443 unsigned int ret_freq = 0;
1444 unsigned long flags;
1445
1446 read_lock_irqsave(&cpufreq_driver_lock, flags);
1447
1448 if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get) {
1449 ret_freq = cpufreq_driver->get(cpu);
1450 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1451 return ret_freq;
1452 }
1453
1454 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
1455
1456 policy = cpufreq_cpu_get(cpu);
1457 if (policy) {
1458 ret_freq = policy->cur;
1459 cpufreq_cpu_put(policy);
1460 }
1461
1462 return ret_freq;
1463 }
1464 EXPORT_SYMBOL(cpufreq_quick_get);
1465
1466 /**
1467 * cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
1468 * @cpu: CPU number
1469 *
1470 * Just return the max possible frequency for a given CPU.
1471 */
1472 unsigned int cpufreq_quick_get_max(unsigned int cpu)
1473 {
1474 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1475 unsigned int ret_freq = 0;
1476
1477 if (policy) {
1478 ret_freq = policy->max;
1479 cpufreq_cpu_put(policy);
1480 }
1481
1482 return ret_freq;
1483 }
1484 EXPORT_SYMBOL(cpufreq_quick_get_max);
1485
1486 static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
1487 {
1488 unsigned int ret_freq = 0;
1489
1490 if (!cpufreq_driver->get)
1491 return ret_freq;
1492
1493 ret_freq = cpufreq_driver->get(policy->cpu);
1494
1495 /*
1496 * Updating inactive policies is invalid, so avoid doing that. Also
1497 * if fast frequency switching is used with the given policy, the check
1498 * against policy->cur is pointless, so skip it in that case too.
1499 */
1500 if (unlikely(policy_is_inactive(policy)) || policy->fast_switch_enabled)
1501 return ret_freq;
1502
1503 if (ret_freq && policy->cur &&
1504 !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
1505 /* verify no discrepancy between actual and
1506 saved value exists */
1507 if (unlikely(ret_freq != policy->cur)) {
1508 cpufreq_out_of_sync(policy, ret_freq);
1509 schedule_work(&policy->update);
1510 }
1511 }
1512
1513 return ret_freq;
1514 }
1515
1516 /**
1517 * cpufreq_get - get the current CPU frequency (in kHz)
1518 * @cpu: CPU number
1519 *
1520 * Get the CPU current (static) CPU frequency
1521 */
1522 unsigned int cpufreq_get(unsigned int cpu)
1523 {
1524 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
1525 unsigned int ret_freq = 0;
1526
1527 if (policy) {
1528 down_read(&policy->rwsem);
1529 ret_freq = __cpufreq_get(policy);
1530 up_read(&policy->rwsem);
1531
1532 cpufreq_cpu_put(policy);
1533 }
1534
1535 return ret_freq;
1536 }
1537 EXPORT_SYMBOL(cpufreq_get);
1538
1539 static unsigned int cpufreq_update_current_freq(struct cpufreq_policy *policy)
1540 {
1541 unsigned int new_freq;
1542
1543 new_freq = cpufreq_driver->get(policy->cpu);
1544 if (!new_freq)
1545 return 0;
1546
1547 if (!policy->cur) {
1548 pr_debug("cpufreq: Driver did not initialize current freq\n");
1549 policy->cur = new_freq;
1550 } else if (policy->cur != new_freq && has_target()) {
1551 cpufreq_out_of_sync(policy, new_freq);
1552 }
1553
1554 return new_freq;
1555 }
1556
1557 static struct subsys_interface cpufreq_interface = {
1558 .name = "cpufreq",
1559 .subsys = &cpu_subsys,
1560 .add_dev = cpufreq_add_dev,
1561 .remove_dev = cpufreq_remove_dev,
1562 };
1563
1564 /*
1565 * In case platform wants some specific frequency to be configured
1566 * during suspend..
1567 */
1568 int cpufreq_generic_suspend(struct cpufreq_policy *policy)
1569 {
1570 int ret;
1571
1572 if (!policy->suspend_freq) {
1573 pr_debug("%s: suspend_freq not defined\n", __func__);
1574 return 0;
1575 }
1576
1577 pr_debug("%s: Setting suspend-freq: %u\n", __func__,
1578 policy->suspend_freq);
1579
1580 ret = __cpufreq_driver_target(policy, policy->suspend_freq,
1581 CPUFREQ_RELATION_H);
1582 if (ret)
1583 pr_err("%s: unable to set suspend-freq: %u. err: %d\n",
1584 __func__, policy->suspend_freq, ret);
1585
1586 return ret;
1587 }
1588 EXPORT_SYMBOL(cpufreq_generic_suspend);
1589
1590 /**
1591 * cpufreq_suspend() - Suspend CPUFreq governors
1592 *
1593 * Called during system wide Suspend/Hibernate cycles for suspending governors
1594 * as some platforms can't change frequency after this point in suspend cycle.
1595 * Because some of the devices (like: i2c, regulators, etc) they use for
1596 * changing frequency are suspended quickly after this point.
1597 */
1598 void cpufreq_suspend(void)
1599 {
1600 struct cpufreq_policy *policy;
1601
1602 if (!cpufreq_driver)
1603 return;
1604
1605 if (!has_target() && !cpufreq_driver->suspend)
1606 goto suspend;
1607
1608 pr_debug("%s: Suspending Governors\n", __func__);
1609
1610 for_each_active_policy(policy) {
1611 if (has_target()) {
1612 down_write(&policy->rwsem);
1613 cpufreq_stop_governor(policy);
1614 up_write(&policy->rwsem);
1615 }
1616
1617 if (cpufreq_driver->suspend && cpufreq_driver->suspend(policy))
1618 pr_err("%s: Failed to suspend driver: %p\n", __func__,
1619 policy);
1620 }
1621
1622 suspend:
1623 cpufreq_suspended = true;
1624 }
1625
1626 /**
1627 * cpufreq_resume() - Resume CPUFreq governors
1628 *
1629 * Called during system wide Suspend/Hibernate cycle for resuming governors that
1630 * are suspended with cpufreq_suspend().
1631 */
1632 void cpufreq_resume(void)
1633 {
1634 struct cpufreq_policy *policy;
1635 int ret;
1636
1637 if (!cpufreq_driver)
1638 return;
1639
1640 cpufreq_suspended = false;
1641
1642 if (!has_target() && !cpufreq_driver->resume)
1643 return;
1644
1645 pr_debug("%s: Resuming Governors\n", __func__);
1646
1647 for_each_active_policy(policy) {
1648 if (cpufreq_driver->resume && cpufreq_driver->resume(policy)) {
1649 pr_err("%s: Failed to resume driver: %p\n", __func__,
1650 policy);
1651 } else if (has_target()) {
1652 down_write(&policy->rwsem);
1653 ret = cpufreq_start_governor(policy);
1654 up_write(&policy->rwsem);
1655
1656 if (ret)
1657 pr_err("%s: Failed to start governor for policy: %p\n",
1658 __func__, policy);
1659 }
1660 }
1661 }
1662
1663 /**
1664 * cpufreq_get_current_driver - return current driver's name
1665 *
1666 * Return the name string of the currently loaded cpufreq driver
1667 * or NULL, if none.
1668 */
1669 const char *cpufreq_get_current_driver(void)
1670 {
1671 if (cpufreq_driver)
1672 return cpufreq_driver->name;
1673
1674 return NULL;
1675 }
1676 EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
1677
1678 /**
1679 * cpufreq_get_driver_data - return current driver data
1680 *
1681 * Return the private data of the currently loaded cpufreq
1682 * driver, or NULL if no cpufreq driver is loaded.
1683 */
1684 void *cpufreq_get_driver_data(void)
1685 {
1686 if (cpufreq_driver)
1687 return cpufreq_driver->driver_data;
1688
1689 return NULL;
1690 }
1691 EXPORT_SYMBOL_GPL(cpufreq_get_driver_data);
1692
1693 /*********************************************************************
1694 * NOTIFIER LISTS INTERFACE *
1695 *********************************************************************/
1696
1697 /**
1698 * cpufreq_register_notifier - register a driver with cpufreq
1699 * @nb: notifier function to register
1700 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1701 *
1702 * Add a driver to one of two lists: either a list of drivers that
1703 * are notified about clock rate changes (once before and once after
1704 * the transition), or a list of drivers that are notified about
1705 * changes in cpufreq policy.
1706 *
1707 * This function may sleep, and has the same return conditions as
1708 * blocking_notifier_chain_register.
1709 */
1710 int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
1711 {
1712 int ret;
1713
1714 if (cpufreq_disabled())
1715 return -EINVAL;
1716
1717 WARN_ON(!init_cpufreq_transition_notifier_list_called);
1718
1719 switch (list) {
1720 case CPUFREQ_TRANSITION_NOTIFIER:
1721 mutex_lock(&cpufreq_fast_switch_lock);
1722
1723 if (cpufreq_fast_switch_count > 0) {
1724 mutex_unlock(&cpufreq_fast_switch_lock);
1725 return -EBUSY;
1726 }
1727 ret = srcu_notifier_chain_register(
1728 &cpufreq_transition_notifier_list, nb);
1729 if (!ret)
1730 cpufreq_fast_switch_count--;
1731
1732 mutex_unlock(&cpufreq_fast_switch_lock);
1733 break;
1734 case CPUFREQ_POLICY_NOTIFIER:
1735 ret = blocking_notifier_chain_register(
1736 &cpufreq_policy_notifier_list, nb);
1737 break;
1738 default:
1739 ret = -EINVAL;
1740 }
1741
1742 return ret;
1743 }
1744 EXPORT_SYMBOL(cpufreq_register_notifier);
1745
1746 /**
1747 * cpufreq_unregister_notifier - unregister a driver with cpufreq
1748 * @nb: notifier block to be unregistered
1749 * @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
1750 *
1751 * Remove a driver from the CPU frequency notifier list.
1752 *
1753 * This function may sleep, and has the same return conditions as
1754 * blocking_notifier_chain_unregister.
1755 */
1756 int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
1757 {
1758 int ret;
1759
1760 if (cpufreq_disabled())
1761 return -EINVAL;
1762
1763 switch (list) {
1764 case CPUFREQ_TRANSITION_NOTIFIER:
1765 mutex_lock(&cpufreq_fast_switch_lock);
1766
1767 ret = srcu_notifier_chain_unregister(
1768 &cpufreq_transition_notifier_list, nb);
1769 if (!ret && !WARN_ON(cpufreq_fast_switch_count >= 0))
1770 cpufreq_fast_switch_count++;
1771
1772 mutex_unlock(&cpufreq_fast_switch_lock);
1773 break;
1774 case CPUFREQ_POLICY_NOTIFIER:
1775 ret = blocking_notifier_chain_unregister(
1776 &cpufreq_policy_notifier_list, nb);
1777 break;
1778 default:
1779 ret = -EINVAL;
1780 }
1781
1782 return ret;
1783 }
1784 EXPORT_SYMBOL(cpufreq_unregister_notifier);
1785
1786
1787 /*********************************************************************
1788 * GOVERNORS *
1789 *********************************************************************/
1790
1791 /**
1792 * cpufreq_driver_fast_switch - Carry out a fast CPU frequency switch.
1793 * @policy: cpufreq policy to switch the frequency for.
1794 * @target_freq: New frequency to set (may be approximate).
1795 *
1796 * Carry out a fast frequency switch without sleeping.
1797 *
1798 * The driver's ->fast_switch() callback invoked by this function must be
1799 * suitable for being called from within RCU-sched read-side critical sections
1800 * and it is expected to select the minimum available frequency greater than or
1801 * equal to @target_freq (CPUFREQ_RELATION_L).
1802 *
1803 * This function must not be called if policy->fast_switch_enabled is unset.
1804 *
1805 * Governors calling this function must guarantee that it will never be invoked
1806 * twice in parallel for the same policy and that it will never be called in
1807 * parallel with either ->target() or ->target_index() for the same policy.
1808 *
1809 * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()
1810 * callback to indicate an error condition, the hardware configuration must be
1811 * preserved.
1812 */
1813 unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,
1814 unsigned int target_freq)
1815 {
1816 target_freq = clamp_val(target_freq, policy->min, policy->max);
1817
1818 return cpufreq_driver->fast_switch(policy, target_freq);
1819 }
1820 EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);
1821
1822 /* Must set freqs->new to intermediate frequency */
1823 static int __target_intermediate(struct cpufreq_policy *policy,
1824 struct cpufreq_freqs *freqs, int index)
1825 {
1826 int ret;
1827
1828 freqs->new = cpufreq_driver->get_intermediate(policy, index);
1829
1830 /* We don't need to switch to intermediate freq */
1831 if (!freqs->new)
1832 return 0;
1833
1834 pr_debug("%s: cpu: %d, switching to intermediate freq: oldfreq: %u, intermediate freq: %u\n",
1835 __func__, policy->cpu, freqs->old, freqs->new);
1836
1837 cpufreq_freq_transition_begin(policy, freqs);
1838 ret = cpufreq_driver->target_intermediate(policy, index);
1839 cpufreq_freq_transition_end(policy, freqs, ret);
1840
1841 if (ret)
1842 pr_err("%s: Failed to change to intermediate frequency: %d\n",
1843 __func__, ret);
1844
1845 return ret;
1846 }
1847
1848 static int __target_index(struct cpufreq_policy *policy, int index)
1849 {
1850 struct cpufreq_freqs freqs = {.old = policy->cur, .flags = 0};
1851 unsigned int intermediate_freq = 0;
1852 unsigned int newfreq = policy->freq_table[index].frequency;
1853 int retval = -EINVAL;
1854 bool notify;
1855
1856 if (newfreq == policy->cur)
1857 return 0;
1858
1859 notify = !(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION);
1860 if (notify) {
1861 /* Handle switching to intermediate frequency */
1862 if (cpufreq_driver->get_intermediate) {
1863 retval = __target_intermediate(policy, &freqs, index);
1864 if (retval)
1865 return retval;
1866
1867 intermediate_freq = freqs.new;
1868 /* Set old freq to intermediate */
1869 if (intermediate_freq)
1870 freqs.old = freqs.new;
1871 }
1872
1873 freqs.new = newfreq;
1874 pr_debug("%s: cpu: %d, oldfreq: %u, new freq: %u\n",
1875 __func__, policy->cpu, freqs.old, freqs.new);
1876
1877 cpufreq_freq_transition_begin(policy, &freqs);
1878 }
1879
1880 retval = cpufreq_driver->target_index(policy, index);
1881 if (retval)
1882 pr_err("%s: Failed to change cpu frequency: %d\n", __func__,
1883 retval);
1884
1885 if (notify) {
1886 cpufreq_freq_transition_end(policy, &freqs, retval);
1887
1888 /*
1889 * Failed after setting to intermediate freq? Driver should have
1890 * reverted back to initial frequency and so should we. Check
1891 * here for intermediate_freq instead of get_intermediate, in
1892 * case we haven't switched to intermediate freq at all.
1893 */
1894 if (unlikely(retval && intermediate_freq)) {
1895 freqs.old = intermediate_freq;
1896 freqs.new = policy->restore_freq;
1897 cpufreq_freq_transition_begin(policy, &freqs);
1898 cpufreq_freq_transition_end(policy, &freqs, 0);
1899 }
1900 }
1901
1902 return retval;
1903 }
1904
1905 int __cpufreq_driver_target(struct cpufreq_policy *policy,
1906 unsigned int target_freq,
1907 unsigned int relation)
1908 {
1909 unsigned int old_target_freq = target_freq;
1910 int index;
1911
1912 if (cpufreq_disabled())
1913 return -ENODEV;
1914
1915 /* Make sure that target_freq is within supported range */
1916 target_freq = clamp_val(target_freq, policy->min, policy->max);
1917
1918 pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
1919 policy->cpu, target_freq, relation, old_target_freq);
1920
1921 /*
1922 * This might look like a redundant call as we are checking it again
1923 * after finding index. But it is left intentionally for cases where
1924 * exactly same freq is called again and so we can save on few function
1925 * calls.
1926 */
1927 if (target_freq == policy->cur)
1928 return 0;
1929
1930 /* Save last value to restore later on errors */
1931 policy->restore_freq = policy->cur;
1932
1933 if (cpufreq_driver->target)
1934 return cpufreq_driver->target(policy, target_freq, relation);
1935
1936 if (!cpufreq_driver->target_index)
1937 return -EINVAL;
1938
1939 index = cpufreq_frequency_table_target(policy, target_freq, relation);
1940
1941 return __target_index(policy, index);
1942 }
1943 EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
1944
1945 int cpufreq_driver_target(struct cpufreq_policy *policy,
1946 unsigned int target_freq,
1947 unsigned int relation)
1948 {
1949 int ret = -EINVAL;
1950
1951 down_write(&policy->rwsem);
1952
1953 ret = __cpufreq_driver_target(policy, target_freq, relation);
1954
1955 up_write(&policy->rwsem);
1956
1957 return ret;
1958 }
1959 EXPORT_SYMBOL_GPL(cpufreq_driver_target);
1960
1961 __weak struct cpufreq_governor *cpufreq_fallback_governor(void)
1962 {
1963 return NULL;
1964 }
1965
1966 static int cpufreq_init_governor(struct cpufreq_policy *policy)
1967 {
1968 int ret;
1969
1970 /* Don't start any governor operations if we are entering suspend */
1971 if (cpufreq_suspended)
1972 return 0;
1973 /*
1974 * Governor might not be initiated here if ACPI _PPC changed
1975 * notification happened, so check it.
1976 */
1977 if (!policy->governor)
1978 return -EINVAL;
1979
1980 if (policy->governor->max_transition_latency &&
1981 policy->cpuinfo.transition_latency >
1982 policy->governor->max_transition_latency) {
1983 struct cpufreq_governor *gov = cpufreq_fallback_governor();
1984
1985 if (gov) {
1986 pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
1987 policy->governor->name, gov->name);
1988 policy->governor = gov;
1989 } else {
1990 return -EINVAL;
1991 }
1992 }
1993
1994 if (!try_module_get(policy->governor->owner))
1995 return -EINVAL;
1996
1997 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
1998
1999 if (policy->governor->init) {
2000 ret = policy->governor->init(policy);
2001 if (ret) {
2002 module_put(policy->governor->owner);
2003 return ret;
2004 }
2005 }
2006
2007 return 0;
2008 }
2009
2010 static void cpufreq_exit_governor(struct cpufreq_policy *policy)
2011 {
2012 if (cpufreq_suspended || !policy->governor)
2013 return;
2014
2015 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2016
2017 if (policy->governor->exit)
2018 policy->governor->exit(policy);
2019
2020 module_put(policy->governor->owner);
2021 }
2022
2023 static int cpufreq_start_governor(struct cpufreq_policy *policy)
2024 {
2025 int ret;
2026
2027 if (cpufreq_suspended)
2028 return 0;
2029
2030 if (!policy->governor)
2031 return -EINVAL;
2032
2033 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2034
2035 if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
2036 cpufreq_update_current_freq(policy);
2037
2038 if (policy->governor->start) {
2039 ret = policy->governor->start(policy);
2040 if (ret)
2041 return ret;
2042 }
2043
2044 if (policy->governor->limits)
2045 policy->governor->limits(policy);
2046
2047 return 0;
2048 }
2049
2050 static void cpufreq_stop_governor(struct cpufreq_policy *policy)
2051 {
2052 if (cpufreq_suspended || !policy->governor)
2053 return;
2054
2055 pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
2056
2057 if (policy->governor->stop)
2058 policy->governor->stop(policy);
2059 }
2060
2061 static void cpufreq_governor_limits(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->limits)
2069 policy->governor->limits(policy);
2070 }
2071
2072 int cpufreq_register_governor(struct cpufreq_governor *governor)
2073 {
2074 int err;
2075
2076 if (!governor)
2077 return -EINVAL;
2078
2079 if (cpufreq_disabled())
2080 return -ENODEV;
2081
2082 mutex_lock(&cpufreq_governor_mutex);
2083
2084 err = -EBUSY;
2085 if (!find_governor(governor->name)) {
2086 err = 0;
2087 list_add(&governor->governor_list, &cpufreq_governor_list);
2088 }
2089
2090 mutex_unlock(&cpufreq_governor_mutex);
2091 return err;
2092 }
2093 EXPORT_SYMBOL_GPL(cpufreq_register_governor);
2094
2095 void cpufreq_unregister_governor(struct cpufreq_governor *governor)
2096 {
2097 struct cpufreq_policy *policy;
2098 unsigned long flags;
2099
2100 if (!governor)
2101 return;
2102
2103 if (cpufreq_disabled())
2104 return;
2105
2106 /* clear last_governor for all inactive policies */
2107 read_lock_irqsave(&cpufreq_driver_lock, flags);
2108 for_each_inactive_policy(policy) {
2109 if (!strcmp(policy->last_governor, governor->name)) {
2110 policy->governor = NULL;
2111 strcpy(policy->last_governor, "\0");
2112 }
2113 }
2114 read_unlock_irqrestore(&cpufreq_driver_lock, flags);
2115
2116 mutex_lock(&cpufreq_governor_mutex);
2117 list_del(&governor->governor_list);
2118 mutex_unlock(&cpufreq_governor_mutex);
2119 return;
2120 }
2121 EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
2122
2123
2124 /*********************************************************************
2125 * POLICY INTERFACE *
2126 *********************************************************************/
2127
2128 /**
2129 * cpufreq_get_policy - get the current cpufreq_policy
2130 * @policy: struct cpufreq_policy into which the current cpufreq_policy
2131 * is written
2132 *
2133 * Reads the current cpufreq policy.
2134 */
2135 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
2136 {
2137 struct cpufreq_policy *cpu_policy;
2138 if (!policy)
2139 return -EINVAL;
2140
2141 cpu_policy = cpufreq_cpu_get(cpu);
2142 if (!cpu_policy)
2143 return -EINVAL;
2144
2145 memcpy(policy, cpu_policy, sizeof(*policy));
2146
2147 cpufreq_cpu_put(cpu_policy);
2148 return 0;
2149 }
2150 EXPORT_SYMBOL(cpufreq_get_policy);
2151
2152 /*
2153 * policy : current policy.
2154 * new_policy: policy to be set.
2155 */
2156 static int cpufreq_set_policy(struct cpufreq_policy *policy,
2157 struct cpufreq_policy *new_policy)
2158 {
2159 struct cpufreq_governor *old_gov;
2160 int ret;
2161
2162 pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
2163 new_policy->cpu, new_policy->min, new_policy->max);
2164
2165 memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
2166
2167 /*
2168 * This check works well when we store new min/max freq attributes,
2169 * because new_policy is a copy of policy with one field updated.
2170 */
2171 if (new_policy->min > new_policy->max)
2172 return -EINVAL;
2173
2174 /* verify the cpu speed can be set within this limit */
2175 ret = cpufreq_driver->verify(new_policy);
2176 if (ret)
2177 return ret;
2178
2179 /* adjust if necessary - all reasons */
2180 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2181 CPUFREQ_ADJUST, new_policy);
2182
2183 /*
2184 * verify the cpu speed can be set within this limit, which might be
2185 * different to the first one
2186 */
2187 ret = cpufreq_driver->verify(new_policy);
2188 if (ret)
2189 return ret;
2190
2191 /* notification of the new policy */
2192 blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
2193 CPUFREQ_NOTIFY, new_policy);
2194
2195 policy->min = new_policy->min;
2196 policy->max = new_policy->max;
2197
2198 policy->cached_target_freq = UINT_MAX;
2199
2200 pr_debug("new min and max freqs are %u - %u kHz\n",
2201 policy->min, policy->max);
2202
2203 if (cpufreq_driver->setpolicy) {
2204 policy->policy = new_policy->policy;
2205 pr_debug("setting range\n");
2206 return cpufreq_driver->setpolicy(new_policy);
2207 }
2208
2209 if (new_policy->governor == policy->governor) {
2210 pr_debug("cpufreq: governor limits update\n");
2211 cpufreq_governor_limits(policy);
2212 return 0;
2213 }
2214
2215 pr_debug("governor switch\n");
2216
2217 /* save old, working values */
2218 old_gov = policy->governor;
2219 /* end old governor */
2220 if (old_gov) {
2221 cpufreq_stop_governor(policy);
2222 cpufreq_exit_governor(policy);
2223 }
2224
2225 /* start new governor */
2226 policy->governor = new_policy->governor;
2227 ret = cpufreq_init_governor(policy);
2228 if (!ret) {
2229 ret = cpufreq_start_governor(policy);
2230 if (!ret) {
2231 pr_debug("cpufreq: governor change\n");
2232 return 0;
2233 }
2234 cpufreq_exit_governor(policy);
2235 }
2236
2237 /* new governor failed, so re-start old one */
2238 pr_debug("starting governor %s failed\n", policy->governor->name);
2239 if (old_gov) {
2240 policy->governor = old_gov;
2241 if (cpufreq_init_governor(policy))
2242 policy->governor = NULL;
2243 else
2244 cpufreq_start_governor(policy);
2245 }
2246
2247 return ret;
2248 }
2249
2250 /**
2251 * cpufreq_update_policy - re-evaluate an existing cpufreq policy
2252 * @cpu: CPU which shall be re-evaluated
2253 *
2254 * Useful for policy notifiers which have different necessities
2255 * at different times.
2256 */
2257 int cpufreq_update_policy(unsigned int cpu)
2258 {
2259 struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
2260 struct cpufreq_policy new_policy;
2261 int ret;
2262
2263 if (!policy)
2264 return -ENODEV;
2265
2266 down_write(&policy->rwsem);
2267
2268 pr_debug("updating policy for CPU %u\n", cpu);
2269 memcpy(&new_policy, policy, sizeof(*policy));
2270 new_policy.min = policy->user_policy.min;
2271 new_policy.max = policy->user_policy.max;
2272
2273 /*
2274 * BIOS might change freq behind our back
2275 * -> ask driver for current freq and notify governors about a change
2276 */
2277 if (cpufreq_driver->get && !cpufreq_driver->setpolicy) {
2278 if (cpufreq_suspended) {
2279 ret = -EAGAIN;
2280 goto unlock;
2281 }
2282 new_policy.cur = cpufreq_update_current_freq(policy);
2283 if (WARN_ON(!new_policy.cur)) {
2284 ret = -EIO;
2285 goto unlock;
2286 }
2287 }
2288
2289 ret = cpufreq_set_policy(policy, &new_policy);
2290
2291 unlock:
2292 up_write(&policy->rwsem);
2293
2294 cpufreq_cpu_put(policy);
2295 return ret;
2296 }
2297 EXPORT_SYMBOL(cpufreq_update_policy);
2298
2299 /*********************************************************************
2300 * BOOST *
2301 *********************************************************************/
2302 static int cpufreq_boost_set_sw(int state)
2303 {
2304 struct cpufreq_policy *policy;
2305 int ret = -EINVAL;
2306
2307 for_each_active_policy(policy) {
2308 if (!policy->freq_table)
2309 continue;
2310
2311 ret = cpufreq_frequency_table_cpuinfo(policy,
2312 policy->freq_table);
2313 if (ret) {
2314 pr_err("%s: Policy frequency update failed\n",
2315 __func__);
2316 break;
2317 }
2318
2319 down_write(&policy->rwsem);
2320 policy->user_policy.max = policy->max;
2321 cpufreq_governor_limits(policy);
2322 up_write(&policy->rwsem);
2323 }
2324
2325 return ret;
2326 }
2327
2328 int cpufreq_boost_trigger_state(int state)
2329 {
2330 unsigned long flags;
2331 int ret = 0;
2332
2333 if (cpufreq_driver->boost_enabled == state)
2334 return 0;
2335
2336 write_lock_irqsave(&cpufreq_driver_lock, flags);
2337 cpufreq_driver->boost_enabled = state;
2338 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2339
2340 ret = cpufreq_driver->set_boost(state);
2341 if (ret) {
2342 write_lock_irqsave(&cpufreq_driver_lock, flags);
2343 cpufreq_driver->boost_enabled = !state;
2344 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2345
2346 pr_err("%s: Cannot %s BOOST\n",
2347 __func__, state ? "enable" : "disable");
2348 }
2349
2350 return ret;
2351 }
2352
2353 static bool cpufreq_boost_supported(void)
2354 {
2355 return likely(cpufreq_driver) && cpufreq_driver->set_boost;
2356 }
2357
2358 static int create_boost_sysfs_file(void)
2359 {
2360 int ret;
2361
2362 ret = sysfs_create_file(cpufreq_global_kobject, &boost.attr);
2363 if (ret)
2364 pr_err("%s: cannot register global BOOST sysfs file\n",
2365 __func__);
2366
2367 return ret;
2368 }
2369
2370 static void remove_boost_sysfs_file(void)
2371 {
2372 if (cpufreq_boost_supported())
2373 sysfs_remove_file(cpufreq_global_kobject, &boost.attr);
2374 }
2375
2376 int cpufreq_enable_boost_support(void)
2377 {
2378 if (!cpufreq_driver)
2379 return -EINVAL;
2380
2381 if (cpufreq_boost_supported())
2382 return 0;
2383
2384 cpufreq_driver->set_boost = cpufreq_boost_set_sw;
2385
2386 /* This will get removed on driver unregister */
2387 return create_boost_sysfs_file();
2388 }
2389 EXPORT_SYMBOL_GPL(cpufreq_enable_boost_support);
2390
2391 int cpufreq_boost_enabled(void)
2392 {
2393 return cpufreq_driver->boost_enabled;
2394 }
2395 EXPORT_SYMBOL_GPL(cpufreq_boost_enabled);
2396
2397 /*********************************************************************
2398 * REGISTER / UNREGISTER CPUFREQ DRIVER *
2399 *********************************************************************/
2400 static enum cpuhp_state hp_online;
2401
2402 /**
2403 * cpufreq_register_driver - register a CPU Frequency driver
2404 * @driver_data: A struct cpufreq_driver containing the values#
2405 * submitted by the CPU Frequency driver.
2406 *
2407 * Registers a CPU Frequency driver to this core code. This code
2408 * returns zero on success, -EEXIST when another driver got here first
2409 * (and isn't unregistered in the meantime).
2410 *
2411 */
2412 int cpufreq_register_driver(struct cpufreq_driver *driver_data)
2413 {
2414 unsigned long flags;
2415 int ret;
2416
2417 if (cpufreq_disabled())
2418 return -ENODEV;
2419
2420 if (!driver_data || !driver_data->verify || !driver_data->init ||
2421 !(driver_data->setpolicy || driver_data->target_index ||
2422 driver_data->target) ||
2423 (driver_data->setpolicy && (driver_data->target_index ||
2424 driver_data->target)) ||
2425 (!!driver_data->get_intermediate != !!driver_data->target_intermediate))
2426 return -EINVAL;
2427
2428 pr_debug("trying to register driver %s\n", driver_data->name);
2429
2430 /* Protect against concurrent CPU online/offline. */
2431 get_online_cpus();
2432
2433 write_lock_irqsave(&cpufreq_driver_lock, flags);
2434 if (cpufreq_driver) {
2435 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2436 ret = -EEXIST;
2437 goto out;
2438 }
2439 cpufreq_driver = driver_data;
2440 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2441
2442 if (driver_data->setpolicy)
2443 driver_data->flags |= CPUFREQ_CONST_LOOPS;
2444
2445 if (cpufreq_boost_supported()) {
2446 ret = create_boost_sysfs_file();
2447 if (ret)
2448 goto err_null_driver;
2449 }
2450
2451 ret = subsys_interface_register(&cpufreq_interface);
2452 if (ret)
2453 goto err_boost_unreg;
2454
2455 if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
2456 list_empty(&cpufreq_policy_list)) {
2457 /* if all ->init() calls failed, unregister */
2458 pr_debug("%s: No CPU initialized for driver %s\n", __func__,
2459 driver_data->name);
2460 goto err_if_unreg;
2461 }
2462
2463 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online",
2464 cpufreq_online,
2465 cpufreq_offline);
2466 if (ret < 0)
2467 goto err_if_unreg;
2468 hp_online = ret;
2469 ret = 0;
2470
2471 pr_debug("driver %s up and running\n", driver_data->name);
2472 goto out;
2473
2474 err_if_unreg:
2475 subsys_interface_unregister(&cpufreq_interface);
2476 err_boost_unreg:
2477 remove_boost_sysfs_file();
2478 err_null_driver:
2479 write_lock_irqsave(&cpufreq_driver_lock, flags);
2480 cpufreq_driver = NULL;
2481 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2482 out:
2483 put_online_cpus();
2484 return ret;
2485 }
2486 EXPORT_SYMBOL_GPL(cpufreq_register_driver);
2487
2488 /**
2489 * cpufreq_unregister_driver - unregister the current CPUFreq driver
2490 *
2491 * Unregister the current CPUFreq driver. Only call this if you have
2492 * the right to do so, i.e. if you have succeeded in initialising before!
2493 * Returns zero if successful, and -EINVAL if the cpufreq_driver is
2494 * currently not initialised.
2495 */
2496 int cpufreq_unregister_driver(struct cpufreq_driver *driver)
2497 {
2498 unsigned long flags;
2499
2500 if (!cpufreq_driver || (driver != cpufreq_driver))
2501 return -EINVAL;
2502
2503 pr_debug("unregistering driver %s\n", driver->name);
2504
2505 /* Protect against concurrent cpu hotplug */
2506 get_online_cpus();
2507 subsys_interface_unregister(&cpufreq_interface);
2508 remove_boost_sysfs_file();
2509 cpuhp_remove_state_nocalls(hp_online);
2510
2511 write_lock_irqsave(&cpufreq_driver_lock, flags);
2512
2513 cpufreq_driver = NULL;
2514
2515 write_unlock_irqrestore(&cpufreq_driver_lock, flags);
2516 put_online_cpus();
2517
2518 return 0;
2519 }
2520 EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
2521
2522 /*
2523 * Stop cpufreq at shutdown to make sure it isn't holding any locks
2524 * or mutexes when secondary CPUs are halted.
2525 */
2526 static struct syscore_ops cpufreq_syscore_ops = {
2527 .shutdown = cpufreq_suspend,
2528 };
2529
2530 struct kobject *cpufreq_global_kobject;
2531 EXPORT_SYMBOL(cpufreq_global_kobject);
2532
2533 static int __init cpufreq_core_init(void)
2534 {
2535 if (cpufreq_disabled())
2536 return -ENODEV;
2537
2538 cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
2539 BUG_ON(!cpufreq_global_kobject);
2540
2541 register_syscore_ops(&cpufreq_syscore_ops);
2542
2543 return 0;
2544 }
2545 core_initcall(cpufreq_core_init);
Linux with added FPC-III support