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