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