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