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