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cpufreq: Fix governor start/stop race condition
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CommitLineData
1da177e4
LT
1/*
2 * linux/include/linux/cpufreq.h
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
335dc333 6 *
1da177e4
LT
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#ifndef _LINUX_CPUFREQ_H
12#define _LINUX_CPUFREQ_H
13
2aacdfff 14#include <asm/cputime.h>
83933af4 15#include <linux/mutex.h>
1da177e4
LT
16#include <linux/notifier.h>
17#include <linux/threads.h>
1da177e4
LT
18#include <linux/kobject.h>
19#include <linux/sysfs.h>
20#include <linux/completion.h>
21#include <linux/workqueue.h>
22#include <linux/cpumask.h>
4e57b681 23#include <asm/div64.h>
1da177e4
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24
25#define CPUFREQ_NAME_LEN 16
4b972f0b 26/* Print length for names. Extra 1 space for accomodating '\n' in prints */
27#define CPUFREQ_NAME_PLEN (CPUFREQ_NAME_LEN + 1)
1da177e4
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28
29
30/*********************************************************************
31 * CPUFREQ NOTIFIER INTERFACE *
32 *********************************************************************/
33
1da177e4
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34#define CPUFREQ_TRANSITION_NOTIFIER (0)
35#define CPUFREQ_POLICY_NOTIFIER (1)
36
6070b5de
SS
37#ifdef CONFIG_CPU_FREQ
38int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
39int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
a7b422cd 40extern void disable_cpufreq(void);
6070b5de
SS
41#else /* CONFIG_CPU_FREQ */
42static inline int cpufreq_register_notifier(struct notifier_block *nb,
43 unsigned int list)
44{
45 return 0;
46}
47static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
48 unsigned int list)
49{
50 return 0;
51}
a7b422cd 52static inline void disable_cpufreq(void) { }
6070b5de 53#endif /* CONFIG_CPU_FREQ */
1da177e4
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54
55/* if (cpufreq_driver->target) exists, the ->governor decides what frequency
56 * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
57 * two generic policies are available:
58 */
59
60#define CPUFREQ_POLICY_POWERSAVE (1)
61#define CPUFREQ_POLICY_PERFORMANCE (2)
62
335dc333
TF
63/* Frequency values here are CPU kHz so that hardware which doesn't run
64 * with some frequencies can complain without having to guess what per
65 * cent / per mille means.
b53cc6ea 66 * Maximum transition latency is in nanoseconds - if it's unknown,
1da177e4
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67 * CPUFREQ_ETERNAL shall be used.
68 */
69
70struct cpufreq_governor;
71
8aa84ad8
TR
72/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
73extern struct kobject *cpufreq_global_kobject;
2361be23
VK
74int cpufreq_get_global_kobject(void);
75void cpufreq_put_global_kobject(void);
76int cpufreq_sysfs_create_file(const struct attribute *attr);
77void cpufreq_sysfs_remove_file(const struct attribute *attr);
8aa84ad8 78
1da177e4
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79#define CPUFREQ_ETERNAL (-1)
80struct cpufreq_cpuinfo {
81 unsigned int max_freq;
82 unsigned int min_freq;
335dc333
TF
83
84 /* in 10^(-9) s = nanoseconds */
85 unsigned int transition_latency;
1da177e4
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86};
87
88struct cpufreq_real_policy {
89 unsigned int min; /* in kHz */
90 unsigned int max; /* in kHz */
335dc333 91 unsigned int policy; /* see above */
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92 struct cpufreq_governor *governor; /* see below */
93};
94
95struct cpufreq_policy {
951fc5f4
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96 /* CPUs sharing clock, require sw coordination */
97 cpumask_var_t cpus; /* Online CPUs only */
98 cpumask_var_t related_cpus; /* Online + Offline CPUs */
99
62b36cc1 100 unsigned int shared_type; /* ACPI: ANY or ALL affected CPUs
3b2d9942 101 should set cpufreq */
b8eed8af
VK
102 unsigned int cpu; /* cpu nr of CPU managing this policy */
103 unsigned int last_cpu; /* cpu nr of previous CPU that managed
104 * this policy */
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105 struct cpufreq_cpuinfo cpuinfo;/* see above */
106
107 unsigned int min; /* in kHz */
108 unsigned int max; /* in kHz */
109 unsigned int cur; /* in kHz, only needed if cpufreq
110 * governors are used */
335dc333 111 unsigned int policy; /* see above */
1da177e4 112 struct cpufreq_governor *governor; /* see below */
7bd353a9 113 void *governor_data;
95731ebb 114 bool governor_enabled; /* governor start/stop flag */
1da177e4 115
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116 struct work_struct update; /* if update_policy() needs to be
117 * called, but you're in IRQ context */
118
119 struct cpufreq_real_policy user_policy;
120
121 struct kobject kobj;
122 struct completion kobj_unregister;
123};
124
b8eed8af
VK
125#define CPUFREQ_ADJUST (0)
126#define CPUFREQ_INCOMPATIBLE (1)
127#define CPUFREQ_NOTIFY (2)
128#define CPUFREQ_START (3)
129#define CPUFREQ_UPDATE_POLICY_CPU (4)
1da177e4 130
62b36cc1 131/* Only for ACPI */
46f18e3a
VP
132#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
133#define CPUFREQ_SHARED_TYPE_HW (1) /* HW does needed coordination */
134#define CPUFREQ_SHARED_TYPE_ALL (2) /* All dependent CPUs should set freq */
135#define CPUFREQ_SHARED_TYPE_ANY (3) /* Freq can be set from any dependent CPU*/
1da177e4 136
2624f90c
FB
137static inline bool policy_is_shared(struct cpufreq_policy *policy)
138{
139 return cpumask_weight(policy->cpus) > 1;
140}
141
1da177e4
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142/******************** cpufreq transition notifiers *******************/
143
144#define CPUFREQ_PRECHANGE (0)
145#define CPUFREQ_POSTCHANGE (1)
146#define CPUFREQ_RESUMECHANGE (8)
42d4dc3f 147#define CPUFREQ_SUSPENDCHANGE (9)
1da177e4
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148
149struct cpufreq_freqs {
150 unsigned int cpu; /* cpu nr */
151 unsigned int old;
152 unsigned int new;
153 u8 flags; /* flags of cpufreq_driver, see below. */
154};
155
156
157/**
158 * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
159 * @old: old value
160 * @div: divisor
161 * @mult: multiplier
162 *
163 *
164 * new = old * mult / div
165 */
166static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
167{
168#if BITS_PER_LONG == 32
169
170 u64 result = ((u64) old) * ((u64) mult);
171 do_div(result, div);
172 return (unsigned long) result;
173
174#elif BITS_PER_LONG == 64
175
176 unsigned long result = old * ((u64) mult);
177 result /= div;
178 return result;
179
180#endif
181};
182
183/*********************************************************************
184 * CPUFREQ GOVERNORS *
185 *********************************************************************/
186
7bd353a9
VK
187#define CPUFREQ_GOV_START 1
188#define CPUFREQ_GOV_STOP 2
189#define CPUFREQ_GOV_LIMITS 3
190#define CPUFREQ_GOV_POLICY_INIT 4
191#define CPUFREQ_GOV_POLICY_EXIT 5
1da177e4
LT
192
193struct cpufreq_governor {
194 char name[CPUFREQ_NAME_LEN];
b394058f 195 int initialized;
335dc333 196 int (*governor) (struct cpufreq_policy *policy,
1da177e4 197 unsigned int event);
9e76988e
VP
198 ssize_t (*show_setspeed) (struct cpufreq_policy *policy,
199 char *buf);
335dc333 200 int (*store_setspeed) (struct cpufreq_policy *policy,
9e76988e 201 unsigned int freq);
1c256245
TR
202 unsigned int max_transition_latency; /* HW must be able to switch to
203 next freq faster than this value in nano secs or we
204 will fallback to performance governor */
1da177e4
LT
205 struct list_head governor_list;
206 struct module *owner;
207};
208
335dc333
TF
209/*
210 * Pass a target to the cpufreq driver.
1da177e4
LT
211 */
212extern int cpufreq_driver_target(struct cpufreq_policy *policy,
213 unsigned int target_freq,
214 unsigned int relation);
215extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
216 unsigned int target_freq,
217 unsigned int relation);
218
219
bf0b90e3 220extern int __cpufreq_driver_getavg(struct cpufreq_policy *policy,
221 unsigned int cpu);
dfde5d62 222
1da177e4
LT
223int cpufreq_register_governor(struct cpufreq_governor *governor);
224void cpufreq_unregister_governor(struct cpufreq_governor *governor);
225
226
227/*********************************************************************
228 * CPUFREQ DRIVER INTERFACE *
229 *********************************************************************/
230
231#define CPUFREQ_RELATION_L 0 /* lowest frequency at or above target */
232#define CPUFREQ_RELATION_H 1 /* highest frequency below or at target */
233
234struct freq_attr;
235
236struct cpufreq_driver {
237 struct module *owner;
238 char name[CPUFREQ_NAME_LEN];
239 u8 flags;
4d5dcc42
VK
240 /*
241 * This should be set by platforms having multiple clock-domains, i.e.
242 * supporting multiple policies. With this sysfs directories of governor
243 * would be created in cpu/cpu<num>/cpufreq/ directory and so they can
244 * use the same governor with different tunables for different clusters.
245 */
246 bool have_governor_per_policy;
1da177e4
LT
247
248 /* needed by all drivers */
249 int (*init) (struct cpufreq_policy *policy);
250 int (*verify) (struct cpufreq_policy *policy);
251
252 /* define one out of two */
253 int (*setpolicy) (struct cpufreq_policy *policy);
254 int (*target) (struct cpufreq_policy *policy,
255 unsigned int target_freq,
256 unsigned int relation);
257
258 /* should be defined, if possible */
259 unsigned int (*get) (unsigned int cpu);
260
261 /* optional */
bf0b90e3 262 unsigned int (*getavg) (struct cpufreq_policy *policy,
263 unsigned int cpu);
e2f74f35 264 int (*bios_limit) (int cpu, unsigned int *limit);
bf0b90e3 265
1da177e4 266 int (*exit) (struct cpufreq_policy *policy);
7ca64e2d 267 int (*suspend) (struct cpufreq_policy *policy);
1da177e4
LT
268 int (*resume) (struct cpufreq_policy *policy);
269 struct freq_attr **attr;
270};
271
272/* flags */
273
335dc333 274#define CPUFREQ_STICKY 0x01 /* the driver isn't removed even if
1da177e4 275 * all ->init() calls failed */
335dc333 276#define CPUFREQ_CONST_LOOPS 0x02 /* loops_per_jiffy or other kernel
1da177e4
LT
277 * "constants" aren't affected by
278 * frequency transitions */
42d4dc3f
BH
279#define CPUFREQ_PM_NO_WARN 0x04 /* don't warn on suspend/resume speed
280 * mismatches */
1da177e4 281
221dee28
LT
282int cpufreq_register_driver(struct cpufreq_driver *driver_data);
283int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
1da177e4
LT
284
285
b43a7ffb
VK
286void cpufreq_notify_transition(struct cpufreq_policy *policy,
287 struct cpufreq_freqs *freqs, unsigned int state);
1da177e4 288
335dc333 289static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
1da177e4
LT
290{
291 if (policy->min < min)
292 policy->min = min;
293 if (policy->max < min)
294 policy->max = min;
295 if (policy->min > max)
296 policy->min = max;
297 if (policy->max > max)
298 policy->max = max;
299 if (policy->min > policy->max)
300 policy->min = policy->max;
301 return;
302}
303
304struct freq_attr {
305 struct attribute attr;
306 ssize_t (*show)(struct cpufreq_policy *, char *);
307 ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
308};
309
6dad2a29
BP
310#define cpufreq_freq_attr_ro(_name) \
311static struct freq_attr _name = \
312__ATTR(_name, 0444, show_##_name, NULL)
313
314#define cpufreq_freq_attr_ro_perm(_name, _perm) \
315static struct freq_attr _name = \
316__ATTR(_name, _perm, show_##_name, NULL)
317
6dad2a29
BP
318#define cpufreq_freq_attr_rw(_name) \
319static struct freq_attr _name = \
320__ATTR(_name, 0644, show_##_name, store_##_name)
321
8aa84ad8
TR
322struct global_attr {
323 struct attribute attr;
324 ssize_t (*show)(struct kobject *kobj,
325 struct attribute *attr, char *buf);
326 ssize_t (*store)(struct kobject *a, struct attribute *b,
327 const char *c, size_t count);
328};
1da177e4 329
6dad2a29
BP
330#define define_one_global_ro(_name) \
331static struct global_attr _name = \
332__ATTR(_name, 0444, show_##_name, NULL)
333
334#define define_one_global_rw(_name) \
335static struct global_attr _name = \
336__ATTR(_name, 0644, show_##_name, store_##_name)
337
ab45bd9b
BP
338struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
339void cpufreq_cpu_put(struct cpufreq_policy *data);
340const char *cpufreq_get_current_driver(void);
6dad2a29 341
1da177e4
LT
342/*********************************************************************
343 * CPUFREQ 2.6. INTERFACE *
344 *********************************************************************/
72a4ce34 345u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
1da177e4
LT
346int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
347int cpufreq_update_policy(unsigned int cpu);
4d5dcc42 348bool have_governor_per_policy(void);
944e9a03 349struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
1da177e4 350
2eca40a8 351#ifdef CONFIG_CPU_FREQ
ff0ce684
LT
352/* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
353unsigned int cpufreq_get(unsigned int cpu);
2eca40a8
RD
354#else
355static inline unsigned int cpufreq_get(unsigned int cpu)
356{
357 return 0;
358}
359#endif
1da177e4 360
ff0ce684 361/* query the last known CPU freq (in kHz). If zero, cpufreq couldn't detect it */
95235ca2
VP
362#ifdef CONFIG_CPU_FREQ
363unsigned int cpufreq_quick_get(unsigned int cpu);
3d737108 364unsigned int cpufreq_quick_get_max(unsigned int cpu);
95235ca2
VP
365#else
366static inline unsigned int cpufreq_quick_get(unsigned int cpu)
367{
368 return 0;
369}
3d737108
JB
370static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
371{
372 return 0;
373}
95235ca2
VP
374#endif
375
1da177e4
LT
376
377/*********************************************************************
378 * CPUFREQ DEFAULT GOVERNOR *
379 *********************************************************************/
380
381
1c256245
TR
382/*
383 Performance governor is fallback governor if any other gov failed to
384 auto load due latency restrictions
385*/
6afde10c 386#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
1da177e4 387extern struct cpufreq_governor cpufreq_gov_performance;
6afde10c 388#endif
1c256245
TR
389#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
390#define CPUFREQ_DEFAULT_GOVERNOR (&cpufreq_gov_performance)
30d221db
AG
391#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
392extern struct cpufreq_governor cpufreq_gov_powersave;
393#define CPUFREQ_DEFAULT_GOVERNOR (&cpufreq_gov_powersave)
1da177e4
LT
394#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
395extern struct cpufreq_governor cpufreq_gov_userspace;
1c256245
TR
396#define CPUFREQ_DEFAULT_GOVERNOR (&cpufreq_gov_userspace)
397#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
398extern struct cpufreq_governor cpufreq_gov_ondemand;
399#define CPUFREQ_DEFAULT_GOVERNOR (&cpufreq_gov_ondemand)
400#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
401extern struct cpufreq_governor cpufreq_gov_conservative;
402#define CPUFREQ_DEFAULT_GOVERNOR (&cpufreq_gov_conservative)
1da177e4
LT
403#endif
404
405
406/*********************************************************************
407 * FREQUENCY TABLE HELPERS *
408 *********************************************************************/
409
410#define CPUFREQ_ENTRY_INVALID ~0
411#define CPUFREQ_TABLE_END ~1
412
413struct cpufreq_frequency_table {
50701588 414 unsigned int driver_data; /* driver specific data, not used by core */
1da177e4
LT
415 unsigned int frequency; /* kHz - doesn't need to be in ascending
416 * order */
417};
418
419int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
420 struct cpufreq_frequency_table *table);
421
422int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
423 struct cpufreq_frequency_table *table);
424
425int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
426 struct cpufreq_frequency_table *table,
427 unsigned int target_freq,
428 unsigned int relation,
429 unsigned int *index);
430
431/* the following 3 funtions are for cpufreq core use only */
432struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
1da177e4
LT
433
434/* the following are really really optional */
435extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
436
335dc333 437void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
1da177e4 438 unsigned int cpu);
b8eed8af 439void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
1da177e4
LT
440
441void cpufreq_frequency_table_put_attr(unsigned int cpu);
1da177e4 442#endif /* _LINUX_CPUFREQ_H */