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/* SPDX-License-Identifier: GPL-2.0 */
/* linux/include/linux/clockchips.h
* This file contains the structure definitions for clockchips.
* If you are not a clockchip, or the time of day code, you should
* not be including this file!
# include <linux/clocksource.h>
# include <linux/cpumask.h>
# include <linux/ktime.h>
# include <linux/notifier.h>
struct clock_event_device;
struct module;
* Possible states of a clock event device.
* DETACHED: Device is not used by clockevents core. Initial state or can be
* reached from SHUTDOWN.
* SHUTDOWN: Device is powered-off. Can be reached from PERIODIC or ONESHOT.
* PERIODIC: Device is programmed to generate events periodically. Can be
* reached from DETACHED or SHUTDOWN.
* ONESHOT: Device is programmed to generate event only once. Can be reached
* ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
* stopped.
enum clock_event_state {
* Clock event features
# define CLOCK_EVT_FEAT_PERIODIC 0x000001
# define CLOCK_EVT_FEAT_ONESHOT 0x000002
# define CLOCK_EVT_FEAT_KTIME 0x000004
* x86(64) specific (mis)features:
* - Clockevent source stops in C3 State and needs broadcast support.
* - Local APIC timer is used as a dummy device.
# define CLOCK_EVT_FEAT_C3STOP 0x000008
# define CLOCK_EVT_FEAT_DUMMY 0x000010
* Core shall set the interrupt affinity dynamically in broadcast mode
# define CLOCK_EVT_FEAT_DYNIRQ 0x000020
# define CLOCK_EVT_FEAT_PERCPU 0x000040
* Clockevent device is based on a hrtimer for broadcast
# define CLOCK_EVT_FEAT_HRTIMER 0x000080
* struct clock_event_device - clock event device descriptor
* @event_handler: Assigned by the framework to be called by the low
* level handler of the event source
* @set_next_event: set next event function using a clocksource delta
* @set_next_ktime: set next event function using a direct ktime value
* @next_event: local storage for the next event in oneshot mode
* @max_delta_ns: maximum delta value in ns
* @min_delta_ns: minimum delta value in ns
* @mult: nanosecond to cycles multiplier
* @shift: nanoseconds to cycles divisor (power of two)
* @state_use_accessors:current state of the device, assigned by the core code
* @features: features
* @retries: number of forced programming retries
* @set_state_periodic: switch state to periodic
* @set_state_oneshot: switch state to oneshot
* @set_state_oneshot_stopped: switch state to oneshot_stopped
* @set_state_shutdown: switch state to shutdown
* @tick_resume: resume clkevt device
* @broadcast: function to broadcast events
* @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
* @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
* @name: ptr to clock event name
* @rating: variable to rate clock event devices
* @irq: IRQ number (only for non CPU local devices)
* @bound_on: Bound on CPU
* @cpumask: cpumask to indicate for which CPUs this device works
* @list: list head for the management code
* @owner: module reference
struct clock_event_device {
void (*event_handler)(struct clock_event_device *);
int (*set_next_event)(unsigned long evt, struct clock_event_device *);
int (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
ktime_t next_event;
u64 max_delta_ns;
u64 min_delta_ns;
u32 mult;
u32 shift;
enum clock_event_state state_use_accessors;
unsigned int features;
unsigned long retries;
int (*set_state_periodic)(struct clock_event_device *);
int (*set_state_oneshot)(struct clock_event_device *);
int (*set_state_oneshot_stopped)(struct clock_event_device *);
int (*set_state_shutdown)(struct clock_event_device *);
int (*tick_resume)(struct clock_event_device *);
void (*broadcast)(const struct cpumask *mask);
void (*suspend)(struct clock_event_device *);
void (*resume)(struct clock_event_device *);
unsigned long min_delta_ticks;
unsigned long max_delta_ticks;
const char *name;
int rating;
int irq;
int bound_on;
const struct cpumask *cpumask;
struct list_head list;
struct module *owner;
} ____cacheline_aligned;
/* Helpers to verify state of a clockevent device */
static inline bool clockevent_state_detached(struct clock_event_device *dev)
return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
static inline bool clockevent_state_periodic(struct clock_event_device *dev)
return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
* Calculate a multiplication factor for scaled math, which is used to convert
* nanoseconds based values to clock ticks:
* clock_ticks = (nanoseconds * factor) >> shift.
* div_sc is the rearranged equation to calculate a factor from a given clock
* ticks / nanoseconds ratio:
* factor = (clock_ticks << shift) / nanoseconds
static inline unsigned long
div_sc(unsigned long ticks, unsigned long nsec, int shift)
u64 tmp = ((u64)ticks) << shift;
do_div(tmp, nsec);
return (unsigned long) tmp;
/* Clock event layer functions */
extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
extern void clockevents_register_device(struct clock_event_device *dev);
extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
extern void clockevents_config_and_register(struct clock_event_device *dev,
u32 freq, unsigned long min_delta,
unsigned long max_delta);
extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
static inline void
clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec)
return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec);
extern void clockevents_suspend(void);
extern void clockevents_resume(void);
extern void tick_broadcast(const struct cpumask *mask);
# else
# define tick_broadcast NULL
# endif
extern int tick_receive_broadcast(void);
# endif
extern void tick_setup_hrtimer_broadcast(void);
extern int tick_check_broadcast_expired(void);
# else
static inline int tick_check_broadcast_expired(void) { return 0; }
static inline void tick_setup_hrtimer_broadcast(void) { }
# endif
static inline void clockevents_suspend(void) { }
static inline void clockevents_resume(void) { }
static inline int tick_check_broadcast_expired(void) { return 0; }
static inline void tick_setup_hrtimer_broadcast(void) { }
#endif /* _LINUX_CLOCKCHIPS_H */