cpufreq.h

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/*
 *  linux/include/linux/cpufreq.h
 *
 *  Copyright (C) 2001 Russell King
 *            (C) 2002 - 2003 Dominik Brodowski <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#ifndef _LINUX_CPUFREQ_H
#define _LINUX_CPUFREQ_H

#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/threads.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/cpumask.h>
#include <asm/div64.h>

#define CPUFREQ_NAME_LEN 16


/*********************************************************************
 *                     CPUFREQ NOTIFIER INTERFACE                    *
 *********************************************************************/

#define CPUFREQ_TRANSITION_NOTIFIER (0)
#define CPUFREQ_POLICY_NOTIFIER     (1)

#ifdef CONFIG_CPU_FREQ
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);
extern void disable_cpufreq(void);
#else       /* CONFIG_CPU_FREQ */
static inline int cpufreq_register_notifier(struct notifier_block *nb,
                        unsigned int list)
{
    return 0;
}
static inline int cpufreq_unregister_notifier(struct notifier_block *nb,
                        unsigned int list)
{
    return 0;
}
static inline void disable_cpufreq(void) { }
#endif      /* CONFIG_CPU_FREQ */

/* if (cpufreq_driver->target) exists, the ->governor decides what frequency
 * within the limits is used. If (cpufreq_driver->setpolicy> exists, these
 * two generic policies are available:
 */

#define CPUFREQ_POLICY_POWERSAVE    (1)
#define CPUFREQ_POLICY_PERFORMANCE  (2)

/* Frequency values here are CPU kHz so that hardware which doesn't run
 * with some frequencies can complain without having to guess what per
 * cent / per mille means.
 * Maximum transition latency is in nanoseconds - if it's unknown,
 * CPUFREQ_ETERNAL shall be used.
 */

struct cpufreq_governor;

/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
extern struct kobject *cpufreq_global_kobject;

#define CPUFREQ_ETERNAL         (-1)
struct cpufreq_cpuinfo {
    unsigned int        max_freq;
    unsigned int        min_freq;

    /* in 10^(-9) s = nanoseconds */
    unsigned int        transition_latency;
};

struct cpufreq_real_policy {
    unsigned int        min;    /* in kHz */
    unsigned int        max;    /* in kHz */
    unsigned int        policy; /* see above */
    struct cpufreq_governor *governor; /* see below */
};

struct cpufreq_policy {
    cpumask_var_t       cpus;   /* CPUs requiring sw coordination */
    cpumask_var_t       related_cpus; /* CPUs with any coordination */
    unsigned int        shared_type; /* ANY or ALL affected CPUs
                        should set cpufreq */
    unsigned int        cpu;    /* cpu nr of registered CPU */
    struct cpufreq_cpuinfo  cpuinfo;/* see above */

    unsigned int        min;    /* in kHz */
    unsigned int        max;    /* in kHz */
    unsigned int        cur;    /* in kHz, only needed if cpufreq
                     * governors are used */
    unsigned int        policy; /* see above */
    struct cpufreq_governor *governor; /* see below */

    struct work_struct  update; /* if update_policy() needs to be
                     * called, but you're in IRQ context */

    struct cpufreq_real_policy  user_policy;

    struct kobject      kobj;
    struct completion   kobj_unregister;
};

#define CPUFREQ_ADJUST      (0)
#define CPUFREQ_INCOMPATIBLE    (1)
#define CPUFREQ_NOTIFY      (2)
#define CPUFREQ_START       (3)

#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
#define CPUFREQ_SHARED_TYPE_HW   (1) /* HW does needed coordination */
#define CPUFREQ_SHARED_TYPE_ALL  (2) /* All dependent CPUs should set freq */
#define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent CPU*/

/******************** cpufreq transition notifiers *******************/

#define CPUFREQ_PRECHANGE   (0)
#define CPUFREQ_POSTCHANGE  (1)
#define CPUFREQ_RESUMECHANGE    (8)
#define CPUFREQ_SUSPENDCHANGE   (9)

struct cpufreq_freqs {
    unsigned int cpu;   /* cpu nr */
    unsigned int old;
    unsigned int new;
    u8 flags;       /* flags of cpufreq_driver, see below. */
};


static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
{
#if BITS_PER_LONG == 32

    u64 result = ((u64) old) * ((u64) mult);
    do_div(result, div);
    return (unsigned long) result;

#elif BITS_PER_LONG == 64

    unsigned long result = old * ((u64) mult);
    result /= div;
    return result;

#endif
};

/*********************************************************************
 *                          CPUFREQ GOVERNORS                        *
 *********************************************************************/

#define CPUFREQ_GOV_START  1
#define CPUFREQ_GOV_STOP   2
#define CPUFREQ_GOV_LIMITS 3

struct cpufreq_governor {
    char    name[CPUFREQ_NAME_LEN];
    int (*governor) (struct cpufreq_policy *policy,
                 unsigned int event);
    ssize_t (*show_setspeed)    (struct cpufreq_policy *policy,
                     char *buf);
    int (*store_setspeed)   (struct cpufreq_policy *policy,
                     unsigned int freq);
    unsigned int max_transition_latency; /* HW must be able to switch to
            next freq faster than this value in nano secs or we
            will fallback to performance governor */
    struct list_head    governor_list;
    struct module       *owner;
};

/*
 * Pass a target to the cpufreq driver.
 */
extern int cpufreq_driver_target(struct cpufreq_policy *policy,
                 unsigned int target_freq,
                 unsigned int relation);
extern int __cpufreq_driver_target(struct cpufreq_policy *policy,
                   unsigned int target_freq,
                   unsigned int relation);


extern int __cpufreq_driver_getavg(struct cpufreq_policy *policy,
                   unsigned int cpu);

int cpufreq_register_governor(struct cpufreq_governor *governor);
void cpufreq_unregister_governor(struct cpufreq_governor *governor);


/*********************************************************************
 *                      CPUFREQ DRIVER INTERFACE                     *
 *********************************************************************/

#define CPUFREQ_RELATION_L 0  /* lowest frequency at or above target */
#define CPUFREQ_RELATION_H 1  /* highest frequency below or at target */

struct freq_attr;

struct cpufreq_driver {
    struct module           *owner;
    char            name[CPUFREQ_NAME_LEN];
    u8          flags;

    /* needed by all drivers */
    int (*init)     (struct cpufreq_policy *policy);
    int (*verify)   (struct cpufreq_policy *policy);

    /* define one out of two */
    int (*setpolicy)    (struct cpufreq_policy *policy);
    int (*target)   (struct cpufreq_policy *policy,
                 unsigned int target_freq,
                 unsigned int relation);

    /* should be defined, if possible */
    unsigned int    (*get)  (unsigned int cpu);

    /* optional */
    unsigned int (*getavg)  (struct cpufreq_policy *policy,
                 unsigned int cpu);
    int (*bios_limit)   (int cpu, unsigned int *limit);

    int (*exit)     (struct cpufreq_policy *policy);
    int (*suspend)  (struct cpufreq_policy *policy);
    int (*resume)   (struct cpufreq_policy *policy);
    struct freq_attr    **attr;
};

/* flags */

#define CPUFREQ_STICKY      0x01    /* the driver isn't removed even if
                     * all ->init() calls failed */
#define CPUFREQ_CONST_LOOPS 0x02    /* loops_per_jiffy or other kernel
                     * "constants" aren't affected by
                     * frequency transitions */
#define CPUFREQ_PM_NO_WARN  0x04    /* don't warn on suspend/resume speed
                     * mismatches */

int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);


void cpufreq_notify_transition(struct cpufreq_freqs *freqs, unsigned int state);


static inline void cpufreq_verify_within_limits(struct cpufreq_policy *policy, unsigned int min, unsigned int max)
{
    if (policy->min < min)
        policy->min = min;
    if (policy->max < min)
        policy->max = min;
    if (policy->min > max)
        policy->min = max;
    if (policy->max > max)
        policy->max = max;
    if (policy->min > policy->max)
        policy->min = policy->max;
    return;
}

struct freq_attr {
    struct attribute attr;
    ssize_t (*show)(struct cpufreq_policy *, char *);
    ssize_t (*store)(struct cpufreq_policy *, const char *, size_t count);
};

#define cpufreq_freq_attr_ro(_name)     \
static struct freq_attr _name =         \
__ATTR(_name, 0444, show_##_name, NULL)

#define cpufreq_freq_attr_ro_perm(_name, _perm) \
static struct freq_attr _name =         \
__ATTR(_name, _perm, show_##_name, NULL)

#define cpufreq_freq_attr_rw(_name)     \
static struct freq_attr _name =         \
__ATTR(_name, 0644, show_##_name, store_##_name)

struct global_attr {
    struct attribute attr;
    ssize_t (*show)(struct kobject *kobj,
            struct attribute *attr, char *buf);
    ssize_t (*store)(struct kobject *a, struct attribute *b,
             const char *c, size_t count);
};

#define define_one_global_ro(_name)     \
static struct global_attr _name =       \
__ATTR(_name, 0444, show_##_name, NULL)

#define define_one_global_rw(_name)     \
static struct global_attr _name =       \
__ATTR(_name, 0644, show_##_name, store_##_name)


/*********************************************************************
 *                        CPUFREQ 2.6. INTERFACE                     *
 *********************************************************************/
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
int cpufreq_update_policy(unsigned int cpu);

#ifdef CONFIG_CPU_FREQ
/* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
unsigned int cpufreq_get(unsigned int cpu);
#else
static inline unsigned int cpufreq_get(unsigned int cpu)
{
    return 0;
}
#endif

/* query the last known CPU freq (in kHz). If zero, cpufreq couldn't detect it */
#ifdef CONFIG_CPU_FREQ
unsigned int cpufreq_quick_get(unsigned int cpu);
unsigned int cpufreq_quick_get_max(unsigned int cpu);
#else
static inline unsigned int cpufreq_quick_get(unsigned int cpu)
{
    return 0;
}
static inline unsigned int cpufreq_quick_get_max(unsigned int cpu)
{
    return 0;
}
#endif


/*********************************************************************
 *                       CPUFREQ DEFAULT GOVERNOR                    *
 *********************************************************************/


/*
  Performance governor is fallback governor if any other gov failed to
  auto load due latency restrictions
*/
#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
extern struct cpufreq_governor cpufreq_gov_performance;
#endif
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE
#define CPUFREQ_DEFAULT_GOVERNOR    (&cpufreq_gov_performance)
#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE)
extern struct cpufreq_governor cpufreq_gov_powersave;
#define CPUFREQ_DEFAULT_GOVERNOR    (&cpufreq_gov_powersave)
#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE)
extern struct cpufreq_governor cpufreq_gov_userspace;
#define CPUFREQ_DEFAULT_GOVERNOR    (&cpufreq_gov_userspace)
#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND)
extern struct cpufreq_governor cpufreq_gov_ondemand;
#define CPUFREQ_DEFAULT_GOVERNOR    (&cpufreq_gov_ondemand)
#elif defined(CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE)
extern struct cpufreq_governor cpufreq_gov_conservative;
#define CPUFREQ_DEFAULT_GOVERNOR    (&cpufreq_gov_conservative)
#endif


/*********************************************************************
 *                     FREQUENCY TABLE HELPERS                       *
 *********************************************************************/

#define CPUFREQ_ENTRY_INVALID ~0
#define CPUFREQ_TABLE_END     ~1

struct cpufreq_frequency_table {
    unsigned int    index;     /* any */
    unsigned int    frequency; /* kHz - doesn't need to be in ascending
                    * order */
};

int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy,
                    struct cpufreq_frequency_table *table);

int cpufreq_frequency_table_verify(struct cpufreq_policy *policy,
                   struct cpufreq_frequency_table *table);

int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
                   struct cpufreq_frequency_table *table,
                   unsigned int target_freq,
                   unsigned int relation,
                   unsigned int *index);

/* the following 3 funtions are for cpufreq core use only */
struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu);
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu);
void   cpufreq_cpu_put(struct cpufreq_policy *data);

/* the following are really really optional */
extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;

void cpufreq_frequency_table_get_attr(struct cpufreq_frequency_table *table,
                      unsigned int cpu);

void cpufreq_frequency_table_put_attr(unsigned int cpu);


#endif /* _LINUX_CPUFREQ_H */