PX4-Autopilot/src/drivers/actuators/modalai_esc/modalai_esc_serial.cpp

/****************************************************************************
 *
 *   Copyright (c) 2020 PX4 Development Team. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    used to endorse or promote products derived from this software
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#include "string.h"
#include "modalai_esc_serial.hpp"

ModalaiEscSerial::ModalaiEscSerial()
{
}

ModalaiEscSerial::~ModalaiEscSerial()
{
	if (_uart_fd >= 0) {
		uart_close();
	}
}

int ModalaiEscSerial::uart_open(const char *dev, speed_t speed)
{
	if (_uart_fd >= 0) {
		PX4_ERR("Port in use: %s (%i)", dev, errno);
		return -1;
	}

	/* Open UART */
#ifdef __PX4_QURT
	_uart_fd = qurt_uart_open(dev, speed);
#else
	_uart_fd = open(dev, O_RDWR | O_NOCTTY | O_NONBLOCK);
#endif

	if (_uart_fd < 0) {
		PX4_ERR("Error opening port: %s (%i)", dev, errno);
		return -1;
	}

#ifndef __PX4_QURT
	/* Back up the original UART configuration to restore it after exit */
	int termios_state;

	if ((termios_state = tcgetattr(_uart_fd, &_orig_cfg)) < 0) {
		PX4_ERR("Error configuring port: tcgetattr %s: %d", dev, termios_state);
		uart_close();
		return -1;
	}

	/* Fill the struct for the new configuration */
	tcgetattr(_uart_fd, &_cfg);

	/* Disable output post-processing */
	_cfg.c_oflag &= ~OPOST;

	_cfg.c_cflag |= (CLOCAL | CREAD);    /* ignore modem controls */
	_cfg.c_cflag &= ~CSIZE;
	_cfg.c_cflag |= CS8;                 /* 8-bit characters */
	_cfg.c_cflag &= ~PARENB;             /* no parity bit */
	_cfg.c_cflag &= ~CSTOPB;             /* only need 1 stop bit */
	_cfg.c_cflag &= ~CRTSCTS;            /* no hardware flowcontrol */

	/* setup for non-canonical mode */
	_cfg.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
	_cfg.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);

	if (cfsetispeed(&_cfg, speed) < 0 || cfsetospeed(&_cfg, speed) < 0) {
		PX4_ERR("Error configuring port: %s: %d (cfsetispeed, cfsetospeed)", dev, termios_state);
		uart_close();
		return -1;
	}

	if ((termios_state = tcsetattr(_uart_fd, TCSANOW, &_cfg)) < 0) {
		PX4_ERR("Error configuring port: %s (tcsetattr)", dev);
		uart_close();
		return -1;
	}

#endif

	_speed =  speed;

	return 0;
}

int ModalaiEscSerial::uart_set_baud(speed_t speed)
{
#ifndef __PX4_QURT

	if (_uart_fd < 0) {
		return -1;
	}

	if (cfsetispeed(&_cfg, speed) < 0) {
		return -1;
	}

	if (tcsetattr(_uart_fd, TCSANOW, &_cfg) < 0) {
		return -1;
	}

	_speed = speed;

	return 0;
#endif

	return -1;
}

int ModalaiEscSerial::uart_close()
{
#ifndef __PX4_QURT

	if (_uart_fd < 0) {
		PX4_ERR("invalid state for closing");
		return -1;
	}

	if (tcsetattr(_uart_fd, TCSANOW, &_orig_cfg)) {
		PX4_ERR("failed restoring uart to original state");
	}

	if (close(_uart_fd)) {
		PX4_ERR("error closing uart");
	}

#endif

	_uart_fd = -1;

	return 0;
}

int ModalaiEscSerial::uart_write(FAR void *buf, size_t len)
{
	if (_uart_fd < 0 || buf == NULL) {
		PX4_ERR("invalid state for writing or buffer");
		return -1;
	}

#ifdef __PX4_QURT
	return qurt_uart_write(_uart_fd, (const char *) buf, len);
#else
	return write(_uart_fd, buf, len);
#endif
}

int ModalaiEscSerial::uart_read(FAR void *buf, size_t len)
{
	if (_uart_fd < 0 || buf == NULL) {
		PX4_ERR("invalid state for reading or buffer");
		return -1;
	}

#ifdef __PX4_QURT
#define ASYNC_UART_READ_WAIT_US 2000
	// The UART read on SLPI is via an asynchronous service so specify a timeout
	// for the return. The driver will poll periodically until the read comes in
	// so this may block for a while. However, it will timeout if no read comes in.
	return qurt_uart_read(_uart_fd, (char *) buf, len, ASYNC_UART_READ_WAIT_US);
#else
	return read(_uart_fd, buf, len);
#endif
}