ardupilot/libraries/AP_Scheduler/AP_Scheduler.cpp

108 lines
3.6 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
* main loop scheduler for APM
* Author: Andrew Tridgell, January 2013
*
* This firmware is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*/
#include <AP_HAL.h>
#include <AP_Scheduler.h>
#include <AP_Param.h>
extern const AP_HAL::HAL& hal;
const AP_Param::GroupInfo AP_Scheduler::var_info[] PROGMEM = {
// @Param: DEBUG
// @DisplayName: Scheduler debug level
// @Description: Set to non-zero to enable scheduler debug messages
// @Values: 0:Disabled,1:Enabled
// @User: Advanced
AP_GROUPINFO("DEBUG", 0, AP_Scheduler, _debug, 0),
AP_GROUPEND
};
// initialise the scheduler
void AP_Scheduler::init(const AP_Scheduler::Task *tasks, uint8_t num_tasks)
{
_tasks = tasks;
_num_tasks = num_tasks;
_last_run = new uint16_t[_num_tasks];
memset(_last_run, 0, sizeof(_last_run[0]*_num_tasks));
}
// one tick has passed
void AP_Scheduler::tick(void)
{
_tick_counter++;
}
/*
run one tick
this will run as many scheduler tasks as we can in the specified time
*/
void AP_Scheduler::run(uint16_t time_available)
{
for (uint8_t i=0; i<_num_tasks; i++) {
uint16_t dt = _tick_counter - _last_run[i];
uint16_t interval_ticks = pgm_read_word(&_tasks[i].interval_ticks);
if (dt >= interval_ticks) {
// this task is due to run. Do we have enough time to run it?
_task_time_allowed = pgm_read_word(&_tasks[i].max_time_micros);
if (dt >= interval_ticks*2) {
// we've slipped a whole run of this task!
if (_debug != 0) {
hal.console->printf_P(PSTR("Scheduler slip task[%u] (%u/%u/%u)\n"),
(unsigned)i,
(unsigned)dt,
(unsigned)interval_ticks,
(unsigned)_task_time_allowed);
}
}
if (_task_time_allowed <= time_available) {
// run it
_task_time_started = hal.scheduler->micros();
task_fn_t func = (task_fn_t)pgm_read_pointer(&_tasks[i].function);
func();
// record the tick counter when we ran. This drives
// when we next run the event
_last_run[i] = _tick_counter;
// work out how long the event actually took
uint32_t time_taken = hal.scheduler->micros() - _task_time_started;
if (time_taken > _task_time_allowed) {
// the event overran!
if (_debug != 0) {
hal.console->printf_P(PSTR("Scheduler overrun task[%u] (%u/%u)\n"),
(unsigned)i,
(unsigned)time_taken,
(unsigned)_task_time_allowed);
}
return;
}
time_available -= time_taken;
}
}
}
}
/*
return number of micros until the current task reaches its deadline
*/
uint16_t AP_Scheduler::time_available_usec(void)
{
uint32_t dt = hal.scheduler->micros() - _task_time_started;
if (dt > _task_time_allowed) {
return 0;
}
return _task_time_allowed - dt;
}