path: root/include/linux/cpufreq.h

/*
 *  linux/include/linux/cpufreq.h
 *
 *  Copyright (C) 2001 Russell King
 *            (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
 *            
 *
 * $Id: cpufreq.h,v 1.36 2003/01/20 17:31:48 db Exp $
 *
 * 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/config.h>
#include <linux/notifier.h>
#include <linux/threads.h>
#include <linux/device.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>

#define CPUFREQ_NAME_LEN 16


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

int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list);
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list);

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

#define CPUFREQ_ALL_CPUS        ((NR_CPUS))


/********************** cpufreq policy notifiers *********************/

#define CPUFREQ_POLICY_POWERSAVE        (1)
#define CPUFREQ_POLICY_PERFORMANCE      (2)
#define CPUFREQ_POLICY_GOVERNOR         (3)

/* 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 microseconds - 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;
};

struct cpufreq_policy {
	unsigned int            cpu;    /* cpu nr or CPUFREQ_ALL_CPUS */
	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 cpufreq_cpuinfo  cpuinfo;     /* see above */
	struct kobject		kobj;
 	struct semaphore	lock;   /* CPU ->setpolicy or ->target may
					   only be called once a time */
};

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


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

#define CPUFREQ_PRECHANGE	(0)
#define CPUFREQ_POSTCHANGE	(1)

struct cpufreq_freqs {
	unsigned int cpu;      /* cpu nr or CPUFREQ_ALL_CPUS */
	unsigned int old;
	unsigned int new;
};


/**
 * cpufreq_scale - "old * mult / div" calculation for large values (32-bit-arch safe)
 * @old:   old value
 * @div:   divisor
 * @mult:  multiplier
 *
 * Needed for loops_per_jiffy and similar calculations.  We do it 
 * this way to avoid math overflow on 32-bit machines.  This will
 * become architecture dependent once high-resolution-timer is
 * merged (or any other thing that introduces sc_math.h).
 *
 *    new = old * mult / div
 */
static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mult)
{
	unsigned long val, carry;

	mult /= 100;
	div  /= 100;
        val   = (old / div) * mult;
        carry = old % div;
	carry = carry * mult / div;

	return carry + val;
};

/*********************************************************************
 *                          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);
	struct list_head	governor_list;
	struct module           *owner;
};

/* pass a target to the cpufreq driver 
 */
inline int cpufreq_driver_target(struct cpufreq_policy *policy,
				 unsigned int target_freq,
				 unsigned int relation);

/* pass an event to the cpufreq governor */
int cpufreq_governor(unsigned int cpu, unsigned int event);

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 {
	/* needed by all drivers */
	int	(*verify)	(struct cpufreq_policy *policy);
	struct cpufreq_policy	*policy;
	char			name[CPUFREQ_NAME_LEN];
	/* define one out of two */
	int	(*setpolicy)	(struct cpufreq_policy *policy);
	int	(*target)	(struct cpufreq_policy *policy,
				 unsigned int target_freq,
				 unsigned int relation);
	struct module           *owner;
	/* optional, for the moment */
	int	(*init)		(struct cpufreq_policy *policy);
	int	(*exit)		(struct cpufreq_policy *policy);
	struct freq_attr	**attr;
};

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_set_policy(struct cpufreq_policy *policy);
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);

#ifdef CONFIG_PM
int cpufreq_restore(void);
#endif

/* the proc_intf.c needs this */
int cpufreq_parse_governor (char *str_governor, unsigned int *policy, struct cpufreq_governor **governor);

#if defined(CONFIG_CPU_FREQ_GOV_USERSPACE) || defined(CONFIG_CPU_FREQ_GOV_USERSPACE_MODULE)
/*********************************************************************
 *                      CPUFREQ USERSPACE GOVERNOR                   *
 *********************************************************************/
extern struct cpufreq_governor cpufreq_gov_userspace;
int cpufreq_gov_userspace_init(void);

int cpufreq_setmax(unsigned int cpu);
int cpufreq_set(unsigned int kHz, unsigned int cpu);
unsigned int cpufreq_get(unsigned int cpu);

#ifdef CONFIG_CPU_FREQ_24_API

/* /proc/sys/cpu */
enum {
	CPU_NR   = 1,           /* compatibilty reasons */
	CPU_NR_0 = 1,
	CPU_NR_1 = 2,
	CPU_NR_2 = 3,
	CPU_NR_3 = 4,
	CPU_NR_4 = 5,
	CPU_NR_5 = 6,
	CPU_NR_6 = 7,
	CPU_NR_7 = 8,
	CPU_NR_8 = 9,
	CPU_NR_9 = 10,
	CPU_NR_10 = 11,
	CPU_NR_11 = 12,
	CPU_NR_12 = 13,
	CPU_NR_13 = 14,
	CPU_NR_14 = 15,
	CPU_NR_15 = 16,
	CPU_NR_16 = 17,
	CPU_NR_17 = 18,
	CPU_NR_18 = 19,
	CPU_NR_19 = 20,
	CPU_NR_20 = 21,
	CPU_NR_21 = 22,
	CPU_NR_22 = 23,
	CPU_NR_23 = 24,
	CPU_NR_24 = 25,
	CPU_NR_25 = 26,
	CPU_NR_26 = 27,
	CPU_NR_27 = 28,
	CPU_NR_28 = 29,
	CPU_NR_29 = 30,
	CPU_NR_30 = 31,
	CPU_NR_31 = 32,
};

/* /proc/sys/cpu/{0,1,...,(NR_CPUS-1)} */
enum {
	CPU_NR_FREQ_MAX = 1,
	CPU_NR_FREQ_MIN = 2,
	CPU_NR_FREQ = 3,
};

#endif /* CONFIG_CPU_FREQ_24_API */

#endif /* CONFIG_CPU_FREQ_GOV_USERSPACE */


/*********************************************************************
 *                     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 */
};

#if defined(CONFIG_CPU_FREQ_TABLE) || defined(CONFIG_CPU_FREQ_TABLE_MODULE)
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 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 /* CONFIG_CPU_FREQ_TABLE */

/* Currently exported only for the proc interface, remove when that goes */
extern struct cpufreq_driver *cpufreq_driver;

#endif /* _LINUX_CPUFREQ_H */