Kernel  |  3.3

下载     查看原文件
C++程序  |  171行  |  5.14 KB
/*  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;

/* Clock event mode commands */
enum clock_event_mode {

/* Clock event notification values */
enum clock_event_nofitiers {

 * Clock event features
#define CLOCK_EVT_FEAT_PERIODIC		0x000001
#define CLOCK_EVT_FEAT_ONESHOT		0x000002
#define CLOCK_EVT_FEAT_KTIME		0x000004
 * x86(64) specific misfeatures:
 * - 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

 * 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)
 * @mode:		operating mode assigned by the management code
 * @features:		features
 * @retries:		number of forced programming retries
 * @set_mode:		set mode function
 * @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)
 * @cpumask:		cpumask to indicate for which CPUs this device works
 * @list:		list head for the management code
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_mode	mode;
	unsigned int		features;
	unsigned long		retries;

	void			(*broadcast)(const struct cpumask *mask);
	void			(*set_mode)(enum clock_event_mode mode,
					    struct clock_event_device *);
	unsigned long		min_delta_ticks;
	unsigned long		max_delta_ticks;

	const char		*name;
	int			rating;
	int			irq;
	const struct cpumask	*cpumask;
	struct list_head	list;
} ____cacheline_aligned;

 * 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)
	uint64_t tmp = ((uint64_t)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 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);

extern void clockevents_exchange_device(struct clock_event_device *old,
					struct clock_event_device *new);
extern void clockevents_set_mode(struct clock_event_device *dev,
				 enum clock_event_mode mode);
extern int clockevents_register_notifier(struct notifier_block *nb);
extern int clockevents_program_event(struct clock_event_device *dev,
				     ktime_t expires, bool force);

extern void clockevents_handle_noop(struct clock_event_device *dev);

static inline void
clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
	return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
				      freq, minsec);

extern void clockevents_notify(unsigned long reason, void *arg);
# define clockevents_notify(reason, arg) do { } while (0)


#define clockevents_notify(reason, arg) do { } while (0)