LXR linux/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/cpumask.h>
  15#include <linux/completion.h>
  16#include <linux/kobject.h>
  17#include <linux/notifier.h>
  18#include <linux/sysfs.h>
  19
  20/*********************************************************************
  21 *                        CPUFREQ INTERFACE                          *
  22 *********************************************************************/
  23/*
  24 * Frequency values here are CPU kHz
  25 *
  26 * Maximum transition latency is in nanoseconds - if it's unknown,
  27 * CPUFREQ_ETERNAL shall be used.
  28 */
  29
  30#define CPUFREQ_ETERNAL                 (-1)
  31#define CPUFREQ_NAME_LEN                16
  32/* Print length for names. Extra 1 space for accomodating '\n' in prints */
  33#define CPUFREQ_NAME_PLEN               (CPUFREQ_NAME_LEN + 1)
  34
  35struct cpufreq_governor;
  36
  37struct cpufreq_freqs {
  38        unsigned int cpu;       /* cpu nr */
  39        unsigned int old;
  40        unsigned int new;
  41        u8 flags;               /* flags of cpufreq_driver, see below. */
  42};
  43
  44struct cpufreq_cpuinfo {
  45        unsigned int            max_freq;
  46        unsigned int            min_freq;
  47
  48        /* in 10^(-9) s = nanoseconds */
  49        unsigned int            transition_latency;
  50};
  51
  52struct cpufreq_real_policy {
  53        unsigned int            min;    /* in kHz */
  54        unsigned int            max;    /* in kHz */
  55        unsigned int            policy; /* see above */
  56        struct cpufreq_governor *governor; /* see below */
  57};
  58
  59struct cpufreq_policy {
  60        /* CPUs sharing clock, require sw coordination */
  61        cpumask_var_t           cpus;   /* Online CPUs only */
  62        cpumask_var_t           related_cpus; /* Online + Offline CPUs */
  63
  64        unsigned int            shared_type; /* ACPI: ANY or ALL affected CPUs
  65                                                should set cpufreq */
  66        unsigned int            cpu;    /* cpu nr of CPU managing this policy */
  67        unsigned int            last_cpu; /* cpu nr of previous CPU that managed
  68                                           * this policy */
  69        struct cpufreq_cpuinfo  cpuinfo;/* see above */
  70
  71        unsigned int            min;    /* in kHz */
  72        unsigned int            max;    /* in kHz */
  73        unsigned int            cur;    /* in kHz, only needed if cpufreq
  74                                         * governors are used */
  75        unsigned int            policy; /* see above */
  76        struct cpufreq_governor *governor; /* see below */
  77        void                    *governor_data;
  78        bool                    governor_enabled; /* governor start/stop flag */
  79
  80        struct work_struct      update; /* if update_policy() needs to be
  81                                         * called, but you're in IRQ context */
  82
  83        struct cpufreq_real_policy      user_policy;
  84
  85        struct list_head        policy_list;
  86        struct kobject          kobj;
  87        struct completion       kobj_unregister;
  88
  89        /*
  90         * The rules for this semaphore:
  91         * - Any routine that wants to read from the policy structure will
  92         *   do a down_read on this semaphore.
  93         * - Any routine that will write to the policy structure and/or may take away
  94         *   the policy altogether (eg. CPU hotplug), will hold this lock in write
  95         *   mode before doing so.
  96         *
  97         * Additional rules:
  98         * - Lock should not be held across
  99         *     __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
 100         */
 101        struct rw_semaphore     rwsem;
 102};
 103
 104/* Only for ACPI */
 105#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
 106#define CPUFREQ_SHARED_TYPE_HW   (1) /* HW does needed coordination */
 107#define CPUFREQ_SHARED_TYPE_ALL  (2) /* All dependent CPUs should set freq */
 108#define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent CPU*/
 109
 110#ifdef CONFIG_CPU_FREQ
 111struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
 112void cpufreq_cpu_put(struct cpufreq_policy *policy);
 113#else
 114static inline struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
 115{
 116        return NULL;
 117}
 118static inline void cpufreq_cpu_put(struct cpufreq_policy *policy) { }
 119#endif
 120
 121static inline bool policy_is_shared(struct cpufreq_policy *policy)
 122{
 123        return cpumask_weight(policy->cpus) > 1;
 124}
 125
 126/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 127extern struct kobject *cpufreq_global_kobject;
 128int cpufreq_get_global_kobject(void);
 129void cpufreq_put_global_kobject(void);
 130int cpufreq_sysfs_create_file(const struct attribute *attr);
 131void cpufreq_sysfs_remove_file(const struct attribute *attr);
 132
 133#ifdef CONFIG_CPU_FREQ
 134unsigned int cpufreq_get(unsigned int cpu);
 135unsigned int cpufreq_quick_get(unsigned int cpu);
 136unsigned int cpufreq_quick_get_max(unsigned int cpu);
 137void disable_cpufreq(void);
 138
 139u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 140int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 141int cpufreq_update_policy(unsigned int cpu);
 142bool have_governor_per_policy(void);
 143struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
 144#else
 145static inline unsigned int cpufreq_get(unsigned int cpu)
 146{
 147        return 0;
 148}
 149static inline unsigned int cpufreq_quick_get(unsigned int cpu)
 150{
 151        return 0;
 152}
 153static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
 154{
 155        return 0;
 156}
 157static inline void disable_cpufreq(void) { }
 158#endif
 159
 160/*********************************************************************
 161 *                      CPUFREQ DRIVER INTERFACE                     *
 162 *********************************************************************/
 163
 164#define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
 165#define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */
 166
 167struct freq_attr {
 168        struct attribute attr;
 169        ssize_t (*show)(struct cpufreq_policy *, char *);
 170        ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
 171};
 172
 173#define cpufreq_freq_attr_ro(_name)             \
 174static struct freq_attr _name =                 \
 175__ATTR(_name, 0444, show_##_name, NULL)
 176
 177#define cpufreq_freq_attr_ro_perm(_name, _perm) \
 178static struct freq_attr _name =                 \
 179__ATTR(_name, _perm, show_##_name, NULL)
 180
 181#define cpufreq_freq_attr_rw(_name)             \
 182static struct freq_attr _name =                 \
 183__ATTR(_name, 0644, show_##_name, store_##_name)
 184
 185struct global_attr {
 186        struct attribute attr;
 187        ssize_t (*show)(struct kobject *kobj,
 188                        struct attribute *attr, char *buf);
 189        ssize_t (*store)(struct kobject *a, struct attribute *b,
 190                         const char *c, size_t count);
 191};
 192
 193#define define_one_global_ro(_name)             \
 194static struct global_attr _name =               \
 195__ATTR(_name, 0444, show_##_name, NULL)
 196
 197#define define_one_global_rw(_name)             \
 198static struct global_attr _name =               \
 199__ATTR(_name, 0644, show_##_name, store_##_name)
 200
 201
 202struct cpufreq_driver {
 203        char                    name[CPUFREQ_NAME_LEN];
 204        u8                      flags;
 205
 206        /* needed by all drivers */
 207        int     (*init)         (struct cpufreq_policy *policy);
 208        int     (*verify)       (struct cpufreq_policy *policy);
 209
 210        /* define one out of two */
 211        int     (*setpolicy)    (struct cpufreq_policy *policy);
 212        int     (*target)       (struct cpufreq_policy *policy, /* Deprecated */
 213                                 unsigned int target_freq,
 214                                 unsigned int relation);
 215        int     (*target_index) (struct cpufreq_policy *policy,
 216                                 unsigned int index);
 217
 218        /* should be defined, if possible */
 219        unsigned int    (*get)  (unsigned int cpu);
 220
 221        /* optional */
 222        int     (*bios_limit)   (int cpu, unsigned int *limit);
 223
 224        int     (*exit)         (struct cpufreq_policy *policy);
 225        int     (*suspend)      (struct cpufreq_policy *policy);
 226        int     (*resume)       (struct cpufreq_policy *policy);
 227        struct freq_attr        **attr;
 228};
 229
 230/* flags */
 231#define CPUFREQ_STICKY          (1 << 0)        /* driver isn't removed even if
 232                                                   all ->init() calls failed */
 233#define CPUFREQ_CONST_LOOPS     (1 << 1)        /* loops_per_jiffy or other
 234                                                   kernel "constants" aren't
 235                                                   affected by frequency
 236                                                   transitions */
 237#define CPUFREQ_PM_NO_WARN      (1 << 2)        /* don't warn on suspend/resume
 238                                                   speed mismatches */
 239
 240/*
 241 * This should be set by platforms having multiple clock-domains, i.e.
 242 * supporting multiple policies. With this sysfs directories of governor would
 243 * be created in cpu/cpu<num>/cpufreq/ directory and so they can use the same
 244 * governor with different tunables for different clusters.
 245 */
 246#define CPUFREQ_HAVE_GOVERNOR_PER_POLICY (1 << 3)
 247
 248/*
 249 * Driver will do POSTCHANGE notifications from outside of their ->target()
 250 * routine and so must set cpufreq_driver->flags with this flag, so that core
 251 * can handle them specially.
 252 */
 253#define CPUFREQ_ASYNC_NOTIFICATION  (1 << 4)
 254
 255int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 256int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 257
 258const char *cpufreq_get_current_driver(void);
 259
 260static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy,
 261                unsigned int min, unsigned int max)
 262{
 263        if (policy->min < min)
 264                policy->min = min;
 265        if (policy->max < min)
 266                policy->max = min;
 267        if (policy->min > max)
 268                policy->min = max;
 269        if (policy->max > max)
 270                policy->max = max;
 271        if (policy->min > policy->max)
 272                policy->min = policy->max;
 273        return;
 274}
 275
 276static inline void
 277cpufreq_verify_within_cpu_limits(struct cpufreq_policy *policy)
 278{
 279        cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 280                        policy->cpuinfo.max_freq);
 281}
 282
 283/*********************************************************************
 284 *                     CPUFREQ NOTIFIER INTERFACE                    *
 285 *********************************************************************/
 286
 287#define CPUFREQ_TRANSITION_NOTIFIER     (0)
 288#define CPUFREQ_POLICY_NOTIFIER         (1)
 289
 290/* Transition notifiers */
 291#define CPUFREQ_PRECHANGE               (0)
 292#define CPUFREQ_POSTCHANGE              (1)
 293#define CPUFREQ_RESUMECHANGE            (8)
 294#define CPUFREQ_SUSPENDCHANGE           (9)
 295
 296/* Policy Notifiers  */
 297#define CPUFREQ_ADJUST                  (0)
 298#define CPUFREQ_INCOMPATIBLE            (1)
 299#define CPUFREQ_NOTIFY                  (2)
 300#define CPUFREQ_START                   (3)
 301#define CPUFREQ_UPDATE_POLICY_CPU       (4)
 302
 303#ifdef CONFIG_CPU_FREQ
 304int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
 305int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
 306
 307void cpufreq_notify_transition(struct cpufreq_policy *policy,
 308                struct cpufreq_freqs *freqs, unsigned int state);
 309
 310#else /* CONFIG_CPU_FREQ */
 311static inline int cpufreq_register_notifier(struct notifier_block *nb,
 312                                                unsigned int list)
 313{
 314        return 0;
 315}
 316static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
 317                                                unsigned int list)
 318{
 319        return 0;
 320}
 321#endif /* !CONFIG_CPU_FREQ */
 322
 323/**
 324 * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch
 325 * safe)
 326 * @old:   old value
 327 * @div:   divisor
 328 * @mult:  multiplier
 329 *
 330 *
 331 * new = old * mult / div
 332 */
 333static inline unsigned long cpufreq_scale(unsigned long old, u_int div,
 334                u_int mult)
 335{
 336#if BITS_PER_LONG == 32
 337        u64 result = ((u64) old) * ((u64) mult);
 338        do_div(result, div);
 339        return (unsigned long) result;
 340
 341#elif BITS_PER_LONG == 64
 342        unsigned long result = old * ((u64) mult);
 343        result /= div;
 344        return result;
 345#endif
 346}
 347
 348/*********************************************************************
 349 *                          CPUFREQ GOVERNORS                        *
 350 *********************************************************************/
 351
 352/*
 353 * If (cpufreq_driver->target) exists, the ->governor decides what frequency
 354 * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
 355 * two generic policies are available:
 356 */
 357#define CPUFREQ_POLICY_POWERSAVE        (1)
 358#define CPUFREQ_POLICY_PERFORMANCE      (2)
 359
 360/* Governor Events */
 361#define CPUFREQ_GOV_START       1
 362#define CPUFREQ_GOV_STOP        2
 363#define CPUFREQ_GOV_LIMITS      3
 364#define CPUFREQ_GOV_POLICY_INIT 4
 365#define CPUFREQ_GOV_POLICY_EXIT 5
 366
 367struct cpufreq_governor {
 368        char    name[CPUFREQ_NAME_LEN];
 369        int     initialized;
 370        int     (*governor)     (struct cpufreq_policy *policy,
 371                                 unsigned int event);
 372        ssize_t (*show_setspeed)        (struct cpufreq_policy *policy,
 373                                         char *buf);
 374        int     (*store_setspeed)       (struct cpufreq_policy *policy,
 375                                         unsigned int freq);
 376        unsigned int max_transition_latency; /* HW must be able to switch to
 377                        next freq faster than this value in nano secs or we
 378                        will fallback to performance governor */
 379        struct list_head        governor_list;
 380        struct module           *owner;
 381};
 382
 383/* Pass a target to the cpufreq driver */
 384int cpufreq_driver_target(struct cpufreq_policy *policy,
 385                                 unsigned int target_freq,
 386                                 unsigned int relation);
 387int __cpufreq_driver_target(struct cpufreq_policy *policy,
 388                                   unsigned int target_freq,
 389                                   unsigned int relation);
 390int cpufreq_register_governor(struct cpufreq_governor *governor);
 391void cpufreq_unregister_governor(struct cpufreq_governor *governor);
 392
 393/* CPUFREQ DEFAULT GOVERNOR */
 394/*
 395 * Performance governor is fallback governor if any other gov failed to auto
 396 * load due latency restrictions
 397 */
 398#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
 399extern struct cpufreq_governor cpufreq_gov_performance;
 400#endif
 401#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
 402#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_performance)
 403#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
 404extern struct cpufreq_governor cpufreq_gov_powersave;
 405#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_powersave)
 406#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
 407extern struct cpufreq_governor cpufreq_gov_userspace;
 408#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_userspace)
 409#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
 410extern struct cpufreq_governor cpufreq_gov_ondemand;
 411#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_ondemand)
 412#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
 413extern struct cpufreq_governor cpufreq_gov_conservative;
 414#define CPUFREQ_DEFAULT_GOVERNOR        (&cpufreq_gov_conservative)
 415#endif
 416
 417/*********************************************************************
 418 *                     FREQUENCY TABLE HELPERS                       *
 419 *********************************************************************/
 420
 421#define CPUFREQ_ENTRY_INVALID ~0
 422#define CPUFREQ_TABLE_END     ~1
 423
 424struct cpufreq_frequency_table {
 425        unsigned int    driver_data; /* driver specific data, not used by core */
 426        unsigned int    frequency; /* kHz - doesn't need to be in ascending
 427                                    * order */
 428};
 429
 430int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
 431                                    struct cpufreq_frequency_table *table);
 432
 433int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
 434                                   struct cpufreq_frequency_table *table);
 435int cpufreq_generic_frequency_table_verify(struct cpufreq_policy *policy);
 436
 437int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 438                                   struct cpufreq_frequency_table *table,
 439                                   unsigned int target_freq,
 440                                   unsigned int relation,
 441                                   unsigned int *index);
 442
 443void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
 444ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
 445
 446/* the following funtion is for cpufreq core use only */
 447struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
 448
 449/* the following are really really optional */
 450extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;
 451extern struct freq_attr *cpufreq_generic_attr[];
 452void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
 453                                      unsigned int cpu);
 454void cpufreq_frequency_table_put_attr(unsigned int cpu);
 455int cpufreq_table_validate_and_show(struct cpufreq_policy *policy,
 456                                      struct cpufreq_frequency_table *table);
 457
 458int cpufreq_generic_init(struct cpufreq_policy *policy,
 459                struct cpufreq_frequency_table *table,
 460                unsigned int transition_latency);
 461static inline int cpufreq_generic_exit(struct cpufreq_policy *policy)
 462{
 463        cpufreq_frequency_table_put_attr(policy->cpu);
 464        return 0;
 465}
 466
 467#endif /* _LINUX_CPUFREQ_H */
 468