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14ee2ac618
The vDSO library should only include the necessary headers required for a userspace library (UAPI and a minimal set of kernel headers). To make this possible it is necessary to isolate from the kernel headers the common parts that are strictly necessary to build the library. Split clocksource.h into linux and common headers to make the latter suitable for inclusion in the vDSO library. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200320145351.32292-9-vincenzo.frascino@arm.com
286 lines
9.0 KiB
C
286 lines
9.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* linux/include/linux/clocksource.h
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*
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* This file contains the structure definitions for clocksources.
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*
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* If you are not a clocksource, or timekeeping code, you should
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* not be including this file!
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*/
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#ifndef _LINUX_CLOCKSOURCE_H
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#define _LINUX_CLOCKSOURCE_H
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#include <linux/types.h>
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#include <linux/timex.h>
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#include <linux/time.h>
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#include <linux/list.h>
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#include <linux/cache.h>
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#include <linux/timer.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <asm/div64.h>
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#include <asm/io.h>
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struct clocksource;
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struct module;
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#if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \
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defined(CONFIG_GENERIC_GETTIMEOFDAY)
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#include <asm/clocksource.h>
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#endif
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#include <vdso/clocksource.h>
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/**
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* struct clocksource - hardware abstraction for a free running counter
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* Provides mostly state-free accessors to the underlying hardware.
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* This is the structure used for system time.
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*
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* @read: Returns a cycle value, passes clocksource as argument
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* @mask: Bitmask for two's complement
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* subtraction of non 64 bit counters
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* @mult: Cycle to nanosecond multiplier
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* @shift: Cycle to nanosecond divisor (power of two)
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* @max_idle_ns: Maximum idle time permitted by the clocksource (nsecs)
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* @maxadj: Maximum adjustment value to mult (~11%)
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* @archdata: Optional arch-specific data
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* @max_cycles: Maximum safe cycle value which won't overflow on
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* multiplication
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* @name: Pointer to clocksource name
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* @list: List head for registration (internal)
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* @rating: Rating value for selection (higher is better)
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* To avoid rating inflation the following
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* list should give you a guide as to how
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* to assign your clocksource a rating
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* 1-99: Unfit for real use
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* Only available for bootup and testing purposes.
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* 100-199: Base level usability.
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* Functional for real use, but not desired.
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* 200-299: Good.
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* A correct and usable clocksource.
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* 300-399: Desired.
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* A reasonably fast and accurate clocksource.
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* 400-499: Perfect
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* The ideal clocksource. A must-use where
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* available.
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* @flags: Flags describing special properties
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* @enable: Optional function to enable the clocksource
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* @disable: Optional function to disable the clocksource
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* @suspend: Optional suspend function for the clocksource
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* @resume: Optional resume function for the clocksource
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* @mark_unstable: Optional function to inform the clocksource driver that
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* the watchdog marked the clocksource unstable
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* @tick_stable: Optional function called periodically from the watchdog
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* code to provide stable syncrhonization points
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* @wd_list: List head to enqueue into the watchdog list (internal)
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* @cs_last: Last clocksource value for clocksource watchdog
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* @wd_last: Last watchdog value corresponding to @cs_last
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* @owner: Module reference, must be set by clocksource in modules
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*
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* Note: This struct is not used in hotpathes of the timekeeping code
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* because the timekeeper caches the hot path fields in its own data
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* structure, so no cache line alignment is required,
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*
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* The pointer to the clocksource itself is handed to the read
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* callback. If you need extra information there you can wrap struct
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* clocksource into your own struct. Depending on the amount of
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* information you need you should consider to cache line align that
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* structure.
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*/
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struct clocksource {
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u64 (*read)(struct clocksource *cs);
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u64 mask;
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u32 mult;
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u32 shift;
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u64 max_idle_ns;
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u32 maxadj;
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#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
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struct arch_clocksource_data archdata;
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#endif
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u64 max_cycles;
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const char *name;
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struct list_head list;
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int rating;
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enum vdso_clock_mode vdso_clock_mode;
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unsigned long flags;
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int (*enable)(struct clocksource *cs);
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void (*disable)(struct clocksource *cs);
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void (*suspend)(struct clocksource *cs);
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void (*resume)(struct clocksource *cs);
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void (*mark_unstable)(struct clocksource *cs);
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void (*tick_stable)(struct clocksource *cs);
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/* private: */
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#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
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/* Watchdog related data, used by the framework */
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struct list_head wd_list;
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u64 cs_last;
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u64 wd_last;
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#endif
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struct module *owner;
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};
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/*
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* Clock source flags bits::
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*/
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#define CLOCK_SOURCE_IS_CONTINUOUS 0x01
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#define CLOCK_SOURCE_MUST_VERIFY 0x02
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#define CLOCK_SOURCE_WATCHDOG 0x10
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#define CLOCK_SOURCE_VALID_FOR_HRES 0x20
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#define CLOCK_SOURCE_UNSTABLE 0x40
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#define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80
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#define CLOCK_SOURCE_RESELECT 0x100
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/* simplify initialization of mask field */
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#define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0)
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static inline u32 clocksource_freq2mult(u32 freq, u32 shift_constant, u64 from)
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{
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/* freq = cyc/from
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* mult/2^shift = ns/cyc
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* mult = ns/cyc * 2^shift
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* mult = from/freq * 2^shift
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* mult = from * 2^shift / freq
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* mult = (from<<shift) / freq
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*/
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u64 tmp = ((u64)from) << shift_constant;
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tmp += freq/2; /* round for do_div */
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do_div(tmp, freq);
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return (u32)tmp;
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}
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/**
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* clocksource_khz2mult - calculates mult from khz and shift
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* @khz: Clocksource frequency in KHz
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* @shift_constant: Clocksource shift factor
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*
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* Helper functions that converts a khz counter frequency to a timsource
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* multiplier, given the clocksource shift value
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*/
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static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
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{
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return clocksource_freq2mult(khz, shift_constant, NSEC_PER_MSEC);
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}
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/**
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* clocksource_hz2mult - calculates mult from hz and shift
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* @hz: Clocksource frequency in Hz
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* @shift_constant: Clocksource shift factor
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*
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* Helper functions that converts a hz counter
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* frequency to a timsource multiplier, given the
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* clocksource shift value
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*/
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static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
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{
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return clocksource_freq2mult(hz, shift_constant, NSEC_PER_SEC);
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}
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/**
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* clocksource_cyc2ns - converts clocksource cycles to nanoseconds
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* @cycles: cycles
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* @mult: cycle to nanosecond multiplier
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* @shift: cycle to nanosecond divisor (power of two)
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*
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* Converts clocksource cycles to nanoseconds, using the given @mult and @shift.
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* The code is optimized for performance and is not intended to work
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* with absolute clocksource cycles (as those will easily overflow),
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* but is only intended to be used with relative (delta) clocksource cycles.
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*
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* XXX - This could use some mult_lxl_ll() asm optimization
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*/
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static inline s64 clocksource_cyc2ns(u64 cycles, u32 mult, u32 shift)
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{
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return ((u64) cycles * mult) >> shift;
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}
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extern int clocksource_unregister(struct clocksource*);
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extern void clocksource_touch_watchdog(void);
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extern void clocksource_change_rating(struct clocksource *cs, int rating);
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extern void clocksource_suspend(void);
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extern void clocksource_resume(void);
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extern struct clocksource * __init clocksource_default_clock(void);
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extern void clocksource_mark_unstable(struct clocksource *cs);
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extern void
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clocksource_start_suspend_timing(struct clocksource *cs, u64 start_cycles);
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extern u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 now);
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extern u64
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clocks_calc_max_nsecs(u32 mult, u32 shift, u32 maxadj, u64 mask, u64 *max_cycles);
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extern void
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clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec);
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/*
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* Don't call __clocksource_register_scale directly, use
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* clocksource_register_hz/khz
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*/
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extern int
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__clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq);
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extern void
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__clocksource_update_freq_scale(struct clocksource *cs, u32 scale, u32 freq);
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/*
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* Don't call this unless you are a default clocksource
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* (AKA: jiffies) and absolutely have to.
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*/
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static inline int __clocksource_register(struct clocksource *cs)
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{
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return __clocksource_register_scale(cs, 1, 0);
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}
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static inline int clocksource_register_hz(struct clocksource *cs, u32 hz)
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{
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return __clocksource_register_scale(cs, 1, hz);
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}
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static inline int clocksource_register_khz(struct clocksource *cs, u32 khz)
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{
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return __clocksource_register_scale(cs, 1000, khz);
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}
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static inline void __clocksource_update_freq_hz(struct clocksource *cs, u32 hz)
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{
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__clocksource_update_freq_scale(cs, 1, hz);
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}
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static inline void __clocksource_update_freq_khz(struct clocksource *cs, u32 khz)
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{
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__clocksource_update_freq_scale(cs, 1000, khz);
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}
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#ifdef CONFIG_ARCH_CLOCKSOURCE_INIT
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extern void clocksource_arch_init(struct clocksource *cs);
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#else
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static inline void clocksource_arch_init(struct clocksource *cs) { }
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#endif
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extern int timekeeping_notify(struct clocksource *clock);
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extern u64 clocksource_mmio_readl_up(struct clocksource *);
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extern u64 clocksource_mmio_readl_down(struct clocksource *);
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extern u64 clocksource_mmio_readw_up(struct clocksource *);
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extern u64 clocksource_mmio_readw_down(struct clocksource *);
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extern int clocksource_mmio_init(void __iomem *, const char *,
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unsigned long, int, unsigned, u64 (*)(struct clocksource *));
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extern int clocksource_i8253_init(void);
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#define TIMER_OF_DECLARE(name, compat, fn) \
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OF_DECLARE_1_RET(timer, name, compat, fn)
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#ifdef CONFIG_TIMER_PROBE
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extern void timer_probe(void);
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#else
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static inline void timer_probe(void) {}
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#endif
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#define TIMER_ACPI_DECLARE(name, table_id, fn) \
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ACPI_DECLARE_PROBE_ENTRY(timer, name, table_id, 0, NULL, 0, fn)
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#endif /* _LINUX_CLOCKSOURCE_H */
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