Time keeping

Macros
#define	HZ   CLOCK_PER_SECOND
	The frequency used for the timer (in Hz)

Functions
void	timer_start (u32 frequency)
	Start the global timekeeping timer. More...
static clock_t	timer_gettick (void)
static bool	timer_tick (void)
	Increment the timekeeping timer's tick count. More...
static time_t	timer_get_ms (void)
static time_t	timer_get_us (void)
static time_t	timer_get_ns (void)
static void	clock_get_time (struct timespec *time)
	Fill a timespec structure with the current time of the day. More...
void	timer_wait_ms (time_t)
	Wait a certain amount of miliseconds. More...

Variables
volatile clock_t	timer_ticks_counter
	This is where we keep track of the number of intervals reported by the timer. More...
volatile u32	timer_kernel_frequency
	Frequency of the global timekeeping timer.
#define	SEC_TO_TICKS(_time)   SEC((_time) * HZ)
	Compute the number of ticks in a given time frame.
#define	MS_TO_TICKS(_time)   MS_TO_SEC(SEC_TO_TICKS(_time))
	Compute the number of ticks in a given time frame.
#define	US_TO_TICKS(_time)   US_TO_SEC(SEC_TO_TICKS(_time))
	Compute the number of ticks in a given time frame.
#define	NS_TO_TICKS(_time)   NS_TO_SEC(SEC_TO_TICKS(_time))
	Compute the number of ticks in a given time frame.
#define	TICKS_TO_SEC(_ticks)   SEC((_ticks) / HZ)
	Convert a number of ticks into a regular time unit.
#define	TICKS_TO_MS(_ticks)   MS(TICKS_TO_SEC(_ticks))
	Convert a number of ticks into a regular time unit.
#define	TICKS_TO_US(_ticks)   US(TICKS_TO_SEC(_ticks))
	Convert a number of ticks into a regular time unit.
#define	TICKS_TO_NS(_ticks)   NS(TICKS_TO_SEC(_ticks))
	Convert a number of ticks into a regular time unit.

Detailed Description

Time

Timer

Any interaction done with the timer should be done through the functions defined inside this header.

Function Documentation

clock_get_time()

static void clock_get_time ( struct timespec *  time )

inlinestatic

FIXME: Change this to use the system's clock once clock_settime(). For now we'll use the system's timer instead.

timer_get_ms()

static time_t timer_get_ms ( void  )

inlinestatic

Returns

the number of miliseconds elapsed since startup.

timer_get_ns()

static time_t timer_get_ns ( void  )

inlinestatic

Returns

the number of nanoseconds elapsed since startup.

timer_get_us()

static time_t timer_get_us ( void  )

inlinestatic

Returns

the number of microseconds elapsed since startup.

timer_gettick()

static clock_t timer_gettick ( void  )

inlinestatic

Returns

the number of timer intervals elapsed since startup

timer_start()

void timer_start

(

u32

frequency

)

Parameters

frequency

The timer's frequency (Hz)

timer_tick()

static bool timer_tick ( void  )

inlinestatic

Returns

true if an overflow occured.

timer_wait_ms()

void timer_wait_ms

(

time_t

ms

)

Warning

Calls to this function are blocking

Variable Documentation

timer_ticks_counter

volatile clock_t timer_ticks_counter

extern

This MUST be incremented EACH time we recieve an interrupt from the global timer.