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root/include/linux/cpufreq.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. cpufreq_register_notifier
  2. cpufreq_unregister_notifier
  3. cpufreq_scale
  4. cpufreq_verify_within_limits
  5. cpufreq_quick_get

/*
 *  linux/include/linux/cpufreq.h
 *
 *  Copyright (C) 2001 Russell King
 *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
 *            
 * 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/device.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);
#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;
}
#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;

#define CPUFREQ_ETERNAL                 (-1)
struct cpufreq_cpuinfo {
        unsigned int            max_freq;
        unsigned int            min_freq;
        unsigned int            transition_latency; /* in 10^(-9) s = nanoseconds */
};

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_t               cpus;   /* CPUs requiring sw coordination */
        cpumask_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. */
};


/**
 * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 * @old:   old value
 * @div:   divisor
 * @mult:  multiplier
 *
 *
 *    new = old * mult / div
 */
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);

int lock_policy_rwsem_read(int cpu);
int lock_policy_rwsem_write(int cpu);
void unlock_policy_rwsem_read(int cpu);
void unlock_policy_rwsem_write(int cpu);


/*********************************************************************
 *                      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     (*exit)         (struct cpufreq_policy *policy);
        int     (*suspend)      (struct cpufreq_policy *policy, pm_message_t pmsg);
        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);
};


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

/* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
unsigned int cpufreq_get(unsigned int cpu);

/* 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);
#else
static inline unsigned int cpufreq_quick_get(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);


/*********************************************************************
 *                     UNIFIED DEBUG HELPERS                         *
 *********************************************************************/

#define CPUFREQ_DEBUG_CORE      1
#define CPUFREQ_DEBUG_DRIVER    2
#define CPUFREQ_DEBUG_GOVERNOR  4

#ifdef CONFIG_CPU_FREQ_DEBUG

extern void cpufreq_debug_printk(unsigned int type, const char *prefix, 
                                 const char *fmt, ...);

#else

#define cpufreq_debug_printk(msg...) do { } while(0)

#endif /* CONFIG_CPU_FREQ_DEBUG */

#endif /* _LINUX_CPUFREQ_H */

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