Implementation of a Low-Power scheduler. More...

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <tick.h>

Data Structures
struct	os_job_t

Macros
#define	s2ostime(s) ((os_time_t) ((int64_t) s * TICK_FREQ))

#define	ms2ostime(ms) ((os_time_t) (((int64_t) ms * TICK_FREQ) / 1000))

#define	us2ostime(us) ((os_time_t) (((int64_t) us * (TICK_FREQ / 64)) / 15625))

#define	ostime2s(t) ((int64_t) (t / TICK_FREQ))

#define	ostime2ms(t) ((int64_t) ((t * (int64_t) 1000) / TICK_FREQ))

#define	ostime2us(t) ((int64_t) ((t * (int64_t) 15625) / (TICK_FREQ / 64)))

Typedefs
typedef int64_t	os_time_t

Functions
void	os_init (void)
	Initializes the Operating System. More...

os_time_t	os_get_time (void)
	Gets the current time. More...

void	os_wait_until (os_time_t time)
	Waits until a given time. More...

void	os_delay (os_time_t time)
	Waits for a given time. More...

os_time_t	os_get_elapsed_time (os_time_t time)
	Returns how much time passed since a given timestamp. More...

uint8_t	os_cancel_job (os_job_t *job)
	Cancels a scheduled job. More...

void	os_post_job (os_job_t job, void(cb)(os_job_t *))
	Posts a job to be executed as soon as possible. More...

void	os_post_delayed_job (os_job_t job, os_time_t time, void(cb)(os_job_t *))
	Posts a job to be executed at a given time. More...

void	os_unblock_powersave (void)
	Allows the system to go to sleep mode. More...

void	os_block_powersave (void)
	Prevents the system from going to sleep mode. More...

void	os_mainloop (void)
	The Operating System mainloop. More...

Detailed Description

Implementation of a Low-Power scheduler.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of Archos nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND AND EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ARCHOS S.A. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Function Documentation

void os_block_powersave ( void )

Prevents the system from going to sleep mode.

This function prevents the system from going to sleep, thus allowing to get the lowest possible latency. It uses a reference counter, so as many calls to os_unblock_powersave() as calls to os_block_powersave() will be needed to re-enable the sleep mode.

uint8_t os_cancel_job ( os_job_t * job )

Cancels a scheduled job.

This function cancels a job that has been previously scheduled (delayed or not).

Parameters

job	The job to cancel.

Return values

uint8_t 1 if the job has been canceled, 0 otherwise.

void os_delay ( os_time_t time )

Waits for a given time.

This function waits for a given time.

Parameters

time	How much time to wait.

os_time_t os_get_elapsed_time ( os_time_t time )

Returns how much time passed since a given timestamp.

This function returns how much time passed since a given timestamp.

Parameters

time	The timestamp used as origin.

Return values

os_time_t

os_time_t os_get_time ( void )

Gets the current time.

This function returns the current time in ticks.

Return values

os_time_t

void os_init ( void )

Initializes the Operating System.

This function initializes the Low-Level system dependencies.

void os_mainloop ( void )

The Operating System mainloop.

This is the Operating System mainloop. It must be called only once, as soon as basic system initialization has been performed.

void os_post_delayed_job	(	os_job_t *	job,
		os_time_t	time,
		void()(os_job_t )	cb
	)

Posts a job to be executed at a given time.

This function posts a job that will be executed at a given time. If the job is already scheduled, it will be canceled first.

Parameters

job	The job handle.
time	The timestamp at which the job needs to be executed.
cb	The callback that will be executed.

void os_post_job	(	os_job_t *	job,
		void()(os_job_t )	cb
	)

Posts a job to be executed as soon as possible.

This function posts a job that will be executed as soon as possible. If the job is already scheduled, it will be canceled first.

Parameters

job	The job handle.
cb	The callback that will be executed.

void os_unblock_powersave ( void )

Allows the system to go to sleep mode.

This function allows the system to go to sleep mode. Any calls to os_block_powersave() must be released at a point by a call to os_unblock_powersave().

void os_wait_until ( os_time_t time )

Waits until a given time.

This function blocks until the given time is reached.

Parameters

time	The timestamp to reach.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Function Documentation