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/*  linux/include/linux/clocksource.h

 *

 *  This file contains the structure definitions for clocksources.

 *

 *  If you are not a clocksource, or timekeeping code, you should

 *  not be including this file!

 */

#ifndef _LINUX_CLOCKSOURCE_H

#define _LINUX_CLOCKSOURCE_H

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include 

struct clocksource;

struct module;

#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA

#include 

#endif

/**

 * struct clocksource - hardware abstraction for a free running counter

 *	Provides mostly state-free accessors to the underlying hardware.

 *	This is the structure used for system time.

 *

 * @name:		ptr to clocksource name

 * @list:		list head for registration

 * @rating:		rating value for selection (higher is better)

 *			To avoid rating inflation the following

 *			list should give you a guide as to how

 *			to assign your clocksource a rating

 *			1-99: Unfit for real use

 *				Only available for bootup and testing purposes.

 *			100-199: Base level usability.

 *				Functional for real use, but not desired.

 *			200-299: Good.

 *				A correct and usable clocksource.

 *			300-399: Desired.

 *				A reasonably fast and accurate clocksource.

 *			400-499: Perfect

 *				The ideal clocksource. A must-use where

 *				available.

 * @read:		returns a cycle value, passes clocksource as argument

 * @enable:		optional function to enable the clocksource

 * @disable:		optional function to disable the clocksource

 * @mask:		bitmask for two's complement

 *			subtraction of non 64 bit counters

 * @mult:		cycle to nanosecond multiplier

 * @shift:		cycle to nanosecond divisor (power of two)

 * @max_idle_ns:	max idle time permitted by the clocksource (nsecs)

 * @maxadj:		maximum adjustment value to mult (~11%)

 * @max_cycles:		maximum safe cycle value which won't overflow on multiplication

 * @flags:		flags describing special properties

 * @archdata:		arch-specific data

 * @suspend:		suspend function for the clocksource, if necessary

 * @resume:		resume function for the clocksource, if necessary

 * @owner:		module reference, must be set by clocksource in modules

 *

 * Note: This struct is not used in hotpathes of the timekeeping code

 * because the timekeeper caches the hot path fields in its own data

 * structure, so no line cache alignment is required,

 *

 * The pointer to the clocksource itself is handed to the read

 * callback. If you need extra information there you can wrap struct

 * clocksource into your own struct. Depending on the amount of

 * information you need you should consider to cache line align that

 * structure.

 */

struct clocksource {

	cycle_t (*read)(struct clocksource *cs);

	cycle_t mask;

	u32 mult;

	u32 shift;

	u64 max_idle_ns;

	u32 maxadj;

#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA

	struct arch_clocksource_data archdata;

#endif

	u64 max_cycles;

	const char *name;

	struct list_head list;

	int rating;

	int (*enable)(struct clocksource *cs);

	void (*disable)(struct clocksource *cs);

	unsigned long flags;

	void (*suspend)(struct clocksource *cs);

	void (*resume)(struct clocksource *cs);

	/* private: */

#ifdef CONFIG_CLOCKSOURCE_WATCHDOG

	/* Watchdog related data, used by the framework */

	struct list_head wd_list;

	cycle_t cs_last;

	cycle_t wd_last;

#endif

	struct module *owner;

};

/*

 * Clock source flags bits::

 */

#define CLOCK_SOURCE_IS_CONTINUOUS		0x01

#define CLOCK_SOURCE_MUST_VERIFY		0x02

#define CLOCK_SOURCE_WATCHDOG			0x10

#define CLOCK_SOURCE_VALID_FOR_HRES		0x20

#define CLOCK_SOURCE_UNSTABLE			0x40

#define CLOCK_SOURCE_SUSPEND_NONSTOP		0x80

#define CLOCK_SOURCE_RESELECT			0x100

/* simplify initialization of mask field */

#define CLOCKSOURCE_MASK(bits) (cycle_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)

static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)

{

	/*  freq = cyc/from

	 *  mult/2^shift  = ns/cyc

	 *  mult = ns/cyc * 2^shift

	 *  mult = from/freq * 2^shift

	 *  mult = from * 2^shift / freq

	 *  mult = (from<

	 */

	u64 tmp = ((u64)from) << shift_constant;

	tmp += freq/2; /* round for do_div */

	do_div(tmp, freq);

	return (u32)tmp;

}

/**

 * clocksource_khz2mult - calculates mult from khz and shift

 * @khz:		Clocksource frequency in KHz

 * @shift_constant:	Clocksource shift factor

 *

 * Helper functions that converts a khz counter frequency to a timsource

 * multiplier, given the clocksource shift value

 */

static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)

{

	return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC);

}

/**

 * clocksource_hz2mult - calculates mult from hz and shift

 * @hz:			Clocksource frequency in Hz

 * @shift_constant:	Clocksource shift factor

 *

 * Helper functions that converts a hz counter

 * frequency to a timsource multiplier, given the

 * clocksource shift value

 */

static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)

{

	return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC);

}

/**

 * clocksource_cyc2ns - converts clocksource cycles to nanoseconds

 * @cycles:	cycles

 * @mult:	cycle to nanosecond multiplier

 * @shift:	cycle to nanosecond divisor (power of two)

 *

 * Converts cycles to nanoseconds, using the given mult and shift.

 *

 * XXX - This could use some mult_lxl_ll() asm optimization

 */

static inline s64 clocksource_cyc2ns(cycle_t cycles, u32 mult, u32 shift)

{

	return ((u64) cycles * mult) >> shift;

}

extern int clocksource_unregister(struct clocksource*);

extern void clocksource_touch_watchdog(void);

extern void clocksource_change_rating(struct clocksource *cs, int rating);

extern void clocksource_suspend(void);

extern void clocksource_resume(void);

extern struct clocksource * __init clocksource_default_clock(void);

extern void clocksource_mark_unstable(struct clocksource *cs);

extern u64

clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles);

extern void

clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec);

/*

 * Don't call __clocksource_register_scale directly, use

 * clocksource_register_hz/khz

 */

extern int

__clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq);

extern void

__clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq);

/*

 * Don't call this unless you are a default clocksource

 * (AKA: jiffies) and absolutely have to.

 */

static inline int __clocksource_register(struct clocksource *cs)

{

	return __clocksource_register_scale(cs, 1, 0);

}

static inline int clocksource_register_hz(struct clocksource *cs, u32 hz)

{

	return __clocksource_register_scale(cs, 1, hz);

}

static inline int clocksource_register_khz(struct clocksource *cs, u32 khz)

{

	return __clocksource_register_scale(cs, 1000, khz);

}

static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz)

{

	__clocksource_update_freq_scale(cs, 1, hz);

}

static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz)

{

	__clocksource_update_freq_scale(cs, 1000, khz);

}

extern int timekeeping_notify(struct clocksource *clock);

extern cycle_t clocksource_mmio_readl_up(struct clocksource *);

extern cycle_t clocksource_mmio_readl_down(struct clocksource *);

extern cycle_t clocksource_mmio_readw_up(struct clocksource *);

extern cycle_t clocksource_mmio_readw_down(struct clocksource *);

extern int clocksource_mmio_init(void __iomem *, const char *,

	unsigned long, int, unsigned, cycle_t (*)(struct clocksource *));

extern int clocksource_i8253_init(void);

#define CLOCKSOURCE_OF_DECLARE(name, compat, fn) \

	OF_DECLARE_1(clksrc, name, compat, fn)

#ifdef CONFIG_CLKSRC_PROBE

extern void clocksource_probe(void);

#else

static inline void clocksource_probe(void) {}

#endif

#define CLOCKSOURCE_ACPI_DECLARE(name, table_id, fn)		\

	ACPI_DECLARE_PROBE_ENTRY(clksrc, name, table_id, 0, NULL, 0, fn)

#endif /* _LINUX_CLOCKSOURCE_H */