mirror of https://github.com/ArduPilot/ardupilot
81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include <AP_HAL/AP_HAL.h>
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#if (CONFIG_HAL_BOARD == HAL_BOARD_APM1 || CONFIG_HAL_BOARD == HAL_BOARD_APM2)
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <AP_HAL/AP_HAL.h>
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#include "AP_HAL_AVR.h"
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#include "Semaphores.h"
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#include "Scheduler.h"
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using namespace AP_HAL_AVR;
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extern const AP_HAL::HAL& hal;
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// Constructor
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AVRSemaphore::AVRSemaphore() : _taken(false) {}
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bool AVRSemaphore::give() {
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if (!_taken) {
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return false;
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} else {
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_taken = false;
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return true;
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}
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}
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bool AVRSemaphore::take(uint32_t timeout_ms) {
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if (hal.scheduler->in_timerprocess()) {
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hal.scheduler->panic(PSTR("PANIC: AVRSemaphore::take used from "
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"inside timer process"));
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return false; /* Never reached - panic does not return */
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}
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return _take_from_mainloop(timeout_ms);
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}
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bool AVRSemaphore::take_nonblocking() {
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if (hal.scheduler->in_timerprocess()) {
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return _take_nonblocking();
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} else {
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return _take_from_mainloop(0);
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}
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}
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bool AVRSemaphore::_take_from_mainloop(uint32_t timeout_ms) {
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/* Try to take immediately */
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if (_take_nonblocking()) {
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return true;
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} else if (timeout_ms == 0) {
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/* Return immediately if timeout is 0 */
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return false;
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}
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uint16_t timeout_ticks = timeout_ms*10;
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do {
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/* Delay 1ms until we can successfully take, or we timed out */
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hal.scheduler->delay_microseconds(100);
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timeout_ticks--;
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if (_take_nonblocking()) {
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return true;
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}
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} while (timeout_ticks > 0);
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return false;
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}
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bool AVRSemaphore::_take_nonblocking() {
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bool result = false;
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uint8_t sreg = SREG;
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cli();
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if (!_taken) {
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_taken = true;
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result = true;
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}
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SREG = sreg;
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return result;
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}
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#endif // CONFIG_HAL_BOARD
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