linux/include/linux/cpufreq.h
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   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 <asm/cputime.h>
  15#include <linux/mutex.h>
  16#include <linux/notifier.h>
  17#include <linux/threads.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/* Print length for names. Extra 1 space for accomodating '\n' in prints */
  27#define CPUFREQ_NAME_PLEN (CPUFREQ_NAME_LEN + 1)
  28
  29
  30/*********************************************************************
  31 *                     CPUFREQ NOTIFIER INTERFACE                    *
  32 *********************************************************************/
  33
  34#define CPUFREQ_TRANSITION_NOTIFIER     (0)
  35#define CPUFREQ_POLICY_NOTIFIER         (1)
  36
  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);
  40extern void disable_cpufreq(void);
  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}
  52static inline void disable_cpufreq(void) { }
  53#endif          /* CONFIG_CPU_FREQ */
  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
  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.
  66 * Maximum transition latency is in nanoseconds - if it's unknown,
  67 * CPUFREQ_ETERNAL shall be used.
  68 */
  69
  70struct cpufreq_governor;
  71
  72/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
  73extern struct kobject *cpufreq_global_kobject;
  74
  75#define CPUFREQ_ETERNAL                 (-1)
  76struct cpufreq_cpuinfo {
  77        unsigned int            max_freq;
  78        unsigned int            min_freq;
  79
  80        /* in 10^(-9) s = nanoseconds */
  81        unsigned int            transition_latency;
  82};
  83
  84struct cpufreq_real_policy {
  85        unsigned int            min;    /* in kHz */
  86        unsigned int            max;    /* in kHz */
  87        unsigned int            policy; /* see above */
  88        struct cpufreq_governor *governor; /* see below */
  89};
  90
  91struct cpufreq_policy {
  92        /* CPUs sharing clock, require sw coordination */
  93        cpumask_var_t           cpus;   /* Online CPUs only */
  94        cpumask_var_t           related_cpus; /* Online + Offline CPUs */
  95
  96        unsigned int            shared_type; /* ACPI: ANY or ALL affected CPUs
  97                                                should set cpufreq */
  98        unsigned int            cpu;    /* cpu nr of CPU managing this policy */
  99        unsigned int            last_cpu; /* cpu nr of previous CPU that managed
 100                                           * this policy */
 101        struct cpufreq_cpuinfo  cpuinfo;/* see above */
 102
 103        unsigned int            min;    /* in kHz */
 104        unsigned int            max;    /* in kHz */
 105        unsigned int            cur;    /* in kHz, only needed if cpufreq
 106                                         * governors are used */
 107        unsigned int            policy; /* see above */
 108        struct cpufreq_governor *governor; /* see below */
 109
 110        struct work_struct      update; /* if update_policy() needs to be
 111                                         * called, but you're in IRQ context */
 112
 113        struct cpufreq_real_policy      user_policy;
 114
 115        struct kobject          kobj;
 116        struct completion       kobj_unregister;
 117};
 118
 119#define CPUFREQ_ADJUST                  (0)
 120#define CPUFREQ_INCOMPATIBLE            (1)
 121#define CPUFREQ_NOTIFY                  (2)
 122#define CPUFREQ_START                   (3)
 123#define CPUFREQ_UPDATE_POLICY_CPU       (4)
 124
 125/* Only for ACPI */
 126#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
 127#define CPUFREQ_SHARED_TYPE_HW   (1) /* HW does needed coordination */
 128#define CPUFREQ_SHARED_TYPE_ALL  (2) /* All dependent CPUs should set freq */
 129#define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent CPU*/
 130
 131static inline bool policy_is_shared(struct cpufreq_policy *policy)
 132{
 133        return cpumask_weight(policy->cpus) > 1;
 134}
 135
 136/******************** cpufreq transition notifiers *******************/
 137
 138#define CPUFREQ_PRECHANGE       (0)
 139#define CPUFREQ_POSTCHANGE      (1)
 140#define CPUFREQ_RESUMECHANGE    (8)
 141#define CPUFREQ_SUSPENDCHANGE   (9)
 142
 143struct cpufreq_freqs {
 144        unsigned int cpu;       /* cpu nr */
 145        unsigned int old;
 146        unsigned int new;
 147        u8 flags;               /* flags of cpufreq_driver, see below. */
 148};
 149
 150
 151/**
 152 * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 153 * @old:   old value
 154 * @div:   divisor
 155 * @mult:  multiplier
 156 *
 157 *
 158 *    new = old * mult / div
 159 */
 160static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
 161{
 162#if BITS_PER_LONG == 32
 163
 164        u64 result = ((u64) old) * ((u64) mult);
 165        do_div(result, div);
 166        return (unsigned long) result;
 167
 168#elif BITS_PER_LONG == 64
 169
 170        unsigned long result = old * ((u64) mult);
 171        result /= div;
 172        return result;
 173
 174#endif
 175};
 176
 177/*********************************************************************
 178 *                          CPUFREQ GOVERNORS                        *
 179 *********************************************************************/
 180
 181#define CPUFREQ_GOV_START  1
 182#define CPUFREQ_GOV_STOP   2
 183#define CPUFREQ_GOV_LIMITS 3
 184
 185struct cpufreq_governor {
 186        char    name[CPUFREQ_NAME_LEN];
 187        int     initialized;
 188        int     (*governor)     (struct cpufreq_policy *policy,
 189                                 unsigned int event);
 190        ssize_t (*show_setspeed)        (struct cpufreq_policy *policy,
 191                                         char *buf);
 192        int     (*store_setspeed)       (struct cpufreq_policy *policy,
 193                                         unsigned int freq);
 194        unsigned int max_transition_latency; /* HW must be able to switch to
 195                        next freq faster than this value in nano secs or we
 196                        will fallback to performance governor */
 197        struct list_head        governor_list;
 198        struct module           *owner;
 199};
 200
 201/*
 202 * Pass a target to the cpufreq driver.
 203 */
 204extern int cpufreq_driver_target(struct cpufreq_policy *policy,
 205                                 unsigned int target_freq,
 206                                 unsigned int relation);
 207extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
 208                                   unsigned int target_freq,
 209                                   unsigned int relation);
 210
 211
 212extern int __cpufreq_driver_getavg(struct cpufreq_policy *policy,
 213                                   unsigned int cpu);
 214
 215int cpufreq_register_governor(struct cpufreq_governor *governor);
 216void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 217
 218
 219/*********************************************************************
 220 *                      CPUFREQ DRIVER INTERFACE                     *
 221 *********************************************************************/
 222
 223#define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 224#define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 225
 226struct freq_attr;
 227
 228struct cpufreq_driver {
 229        struct module           *owner;
 230        char                    name[CPUFREQ_NAME_LEN];
 231        u8                      flags;
 232
 233        /* needed by all drivers */
 234        int     (*init)         (struct cpufreq_policy *policy);
 235        int     (*verify)       (struct cpufreq_policy *policy);
 236
 237        /* define one out of two */
 238        int     (*setpolicy)    (struct cpufreq_policy *policy);
 239        int     (*target)       (struct cpufreq_policy *policy,
 240                                 unsigned int target_freq,
 241                                 unsigned int relation);
 242
 243        /* should be defined, if possible */
 244        unsigned int    (*get)  (unsigned int cpu);
 245
 246        /* optional */
 247        unsigned int (*getavg)  (struct cpufreq_policy *policy,
 248                                 unsigned int cpu);
 249        int     (*bios_limit)   (int cpu, unsigned int *limit);
 250
 251        int     (*exit)         (struct cpufreq_policy *policy);
 252        int     (*suspend)      (struct cpufreq_policy *policy);
 253        int     (*resume)       (struct cpufreq_policy *policy);
 254        struct freq_attr        **attr;
 255};
 256
 257/* flags */
 258
 259#define CPUFREQ_STICKY          0x01    /* the driver isn't removed even if
 260                                         * all ->init() calls failed */
 261#define CPUFREQ_CONST_LOOPS     0x02    /* loops_per_jiffy or other kernel
 262                                         * "constants" aren't affected by
 263                                         * frequency transitions */
 264#define CPUFREQ_PM_NO_WARN      0x04    /* don't warn on suspend/resume speed
 265                                         * mismatches */
 266
 267int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 268int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 269
 270
 271void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);
 272
 273
 274static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
 275{
 276        if (policy->min < min)
 277                policy->min = min;
 278        if (policy->max < min)
 279                policy->max = min;
 280        if (policy->min > max)
 281                policy->min = max;
 282        if (policy->max > max)
 283                policy->max = max;
 284        if (policy->min > policy->max)
 285                policy->min = policy->max;
 286        return;
 287}
 288
 289struct freq_attr {
 290        struct attribute attr;
 291        ssize_t (*show)(struct cpufreq_policy *, char *);
 292        ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 293};
 294
 295#define cpufreq_freq_attr_ro(_name)             \
 296static struct freq_attr _name =                 \
 297__ATTR(_name, 0444, show_##_name, NULL)
 298
 299#define cpufreq_freq_attr_ro_perm(_name, _perm) \
 300static struct freq_attr _name =                 \
 301__ATTR(_name, _perm, show_##_name, NULL)
 302
 303#define cpufreq_freq_attr_rw(_name)             \
 304static struct freq_attr _name =                 \
 305__ATTR(_name, 0644, show_##_name, store_##_name)
 306
 307struct global_attr {
 308        struct attribute attr;
 309        ssize_t (*show)(struct kobject *kobj,
 310                        struct attribute *attr, char *buf);
 311        ssize_t (*store)(struct kobject *a, struct attribute *b,
 312                         const char *c, size_t count);
 313};
 314
 315#define define_one_global_ro(_name)             \
 316static struct global_attr _name =               \
 317__ATTR(_name, 0444, show_##_name, NULL)
 318
 319#define define_one_global_rw(_name)             \
 320static struct global_attr _name =               \
 321__ATTR(_name, 0644, show_##_name, store_##_name)
 322
 323struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
 324void cpufreq_cpu_put(struct cpufreq_policy *data);
 325const char *cpufreq_get_current_driver(void);
 326
 327/*********************************************************************
 328 *                        CPUFREQ 2.6. INTERFACE                     *
 329 *********************************************************************/
 330int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 331int cpufreq_update_policy(unsigned int cpu);
 332
 333#ifdef CONFIG_CPU_FREQ
 334/* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
 335unsigned int cpufreq_get(unsigned int cpu);
 336#else
 337static inline unsigned int cpufreq_get(unsigned int cpu)
 338{
 339        return 0;
 340}
 341#endif
 342
 343/* query the last known CPU freq (in kHz). If zero, cpufreq couldn't detect it */
 344#ifdef CONFIG_CPU_FREQ
 345unsigned int cpufreq_quick_get(unsigned int cpu);
 346unsigned int cpufreq_quick_get_max(unsigned int cpu);
 347#else
 348static inline unsigned int cpufreq_quick_get(unsigned int cpu)
 349{
 350        return 0;
 351}
 352static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
 353{
 354        return 0;
 355}
 356#endif
 357
 358
 359/*********************************************************************
 360 *                       CPUFREQ DEFAULT GOVERNOR                    *
 361 *********************************************************************/
 362
 363
 364/*
 365  Performance governor is fallback governor if any other gov failed to
 366  auto load due latency restrictions
 367*/
 368#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
 369extern struct cpufreq_governor cpufreq_gov_performance;
 370#endif
 371#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 372#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_performance)
 373#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
 374extern struct cpufreq_governor cpufreq_gov_powersave;
 375#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_powersave)
 376#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 377extern struct cpufreq_governor cpufreq_gov_userspace;
 378#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_userspace)
 379#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
 380extern struct cpufreq_governor cpufreq_gov_ondemand;
 381#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_ondemand)
 382#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
 383extern struct cpufreq_governor cpufreq_gov_conservative;
 384#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_conservative)
 385#endif
 386
 387
 388/*********************************************************************
 389 *                     FREQUENCY TABLE HELPERS                       *
 390 *********************************************************************/
 391
 392#define CPUFREQ_ENTRY_INVALID ~0
 393#define CPUFREQ_TABLE_END     ~1
 394
 395struct cpufreq_frequency_table {
 396        unsigned int    index;     /* any */
 397        unsigned int    frequency; /* kHz - doesn't need to be in ascending
 398                                    * order */
 399};
 400
 401int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 402                                    struct cpufreq_frequency_table *table);
 403
 404int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 405                                   struct cpufreq_frequency_table *table);
 406
 407int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 408                                   struct cpufreq_frequency_table *table,
 409                                   unsigned int target_freq,
 410                                   unsigned int relation,
 411                                   unsigned int *index);
 412
 413/* the following 3 funtions are for cpufreq core use only */
 414struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 415
 416/* the following are really really optional */
 417extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 418
 419void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 420                                      unsigned int cpu);
 421void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
 422
 423void cpufreq_frequency_table_put_attr(unsigned int cpu);
 424#endif /* _LINUX_CPUFREQ_H */
 425
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