| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* 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 <linux/types.h> |
| #include <linux/timex.h> |
| #include <linux/time.h> |
| #include <linux/list.h> |
| #include <linux/cache.h> |
| #include <linux/timer.h> |
| #include <linux/init.h> |
| #include <linux/of.h> |
| #include <asm/div64.h> |
| #include <asm/io.h> |
| |
| struct clocksource; |
| struct module; |
| |
| #if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \ |
| defined(CONFIG_GENERIC_GETTIMEOFDAY) |
| #include <asm/clocksource.h> |
| #endif |
| |
| #include <vdso/clocksource.h> |
| |
| /** |
| * 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. |
| * |
| * @read: Returns a cycle value, passes clocksource as argument |
| * @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: Maximum idle time permitted by the clocksource (nsecs) |
| * @maxadj: Maximum adjustment value to mult (~11%) |
| * @archdata: Optional arch-specific data |
| * @max_cycles: Maximum safe cycle value which won't overflow on |
| * multiplication |
| * @name: Pointer to clocksource name |
| * @list: List head for registration (internal) |
| * @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. |
| * @flags: Flags describing special properties |
| * @enable: Optional function to enable the clocksource |
| * @disable: Optional function to disable the clocksource |
| * @suspend: Optional suspend function for the clocksource |
| * @resume: Optional resume function for the clocksource |
| * @mark_unstable: Optional function to inform the clocksource driver that |
| * the watchdog marked the clocksource unstable |
| * @tick_stable: Optional function called periodically from the watchdog |
| * code to provide stable syncrhonization points |
| * @wd_list: List head to enqueue into the watchdog list (internal) |
| * @cs_last: Last clocksource value for clocksource watchdog |
| * @wd_last: Last watchdog value corresponding to @cs_last |
| * @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 cache line 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 { |
| u64 (*read)(struct clocksource *cs); |
| u64 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; |
| enum vdso_clock_mode vdso_clock_mode; |
| unsigned long flags; |
| |
| int (*enable)(struct clocksource *cs); |
| void (*disable)(struct clocksource *cs); |
| void (*suspend)(struct clocksource *cs); |
| void (*resume)(struct clocksource *cs); |
| void (*mark_unstable)(struct clocksource *cs); |
| void (*tick_stable)(struct clocksource *cs); |
| |
| /* private: */ |
| #ifdef CONFIG_CLOCKSOURCE_WATCHDOG |
| /* Watchdog related data, used by the framework */ |
| struct list_head wd_list; |
| u64 cs_last; |
| u64 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) GENMASK_ULL((bits) - 1, 0) |
| |
| 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<<shift) / freq |
| */ |
| 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 clocksource cycles to nanoseconds, using the given @mult and @shift. |
| * The code is optimized for performance and is not intended to work |
| * with absolute clocksource cycles (as those will easily overflow), |
| * but is only intended to be used with relative (delta) clocksource cycles. |
| * |
| * XXX - This could use some mult_lxl_ll() asm optimization |
| */ |
| static inline s64 clocksource_cyc2ns(u64 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 void |
| clocksource_start_suspend_timing(struct clocksource *cs, u64 start_cycles); |
| extern u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 now); |
| |
| 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); |
| } |
| |
| #ifdef CONFIG_ARCH_CLOCKSOURCE_INIT |
| extern void clocksource_arch_init(struct clocksource *cs); |
| #else |
| static inline void clocksource_arch_init(struct clocksource *cs) { } |
| #endif |
| |
| extern int timekeeping_notify(struct clocksource *clock); |
| |
| extern u64 clocksource_mmio_readl_up(struct clocksource *); |
| extern u64 clocksource_mmio_readl_down(struct clocksource *); |
| extern u64 clocksource_mmio_readw_up(struct clocksource *); |
| extern u64 clocksource_mmio_readw_down(struct clocksource *); |
| |
| extern int clocksource_mmio_init(void __iomem *, const char *, |
| unsigned long, int, unsigned, u64 (*)(struct clocksource *)); |
| |
| extern int clocksource_i8253_init(void); |
| |
| #define TIMER_OF_DECLARE(name, compat, fn) \ |
| OF_DECLARE_1_RET(timer, name, compat, fn) |
| |
| #ifdef CONFIG_TIMER_PROBE |
| extern void timer_probe(void); |
| #else |
| static inline void timer_probe(void) {} |
| #endif |
| |
| #define TIMER_ACPI_DECLARE(name, table_id, fn) \ |
| ACPI_DECLARE_PROBE_ENTRY(timer, name, table_id, 0, NULL, 0, fn) |
| |
| #endif /* _LINUX_CLOCKSOURCE_H */ |