/*
 * Copyright (C) 2009 Nicole Faerber <nicole.faerber@dpin.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdint.h>
#include <termios.h>


static int fd = -1;

int open_uart(char *device, speed_t baud)
{
	struct termios ti;

	if (!device)
		device = "/dev/ttyS0";
	fd = open(device, O_RDWR | O_NOCTTY);
	if (fd < 0) {
		fprintf(stderr, "Can't open serial port '%s': %s (%d)\n", device, strerror(errno), errno);
		fd = -1;
		return -1;
	}
	tcflush(fd, TCIOFLUSH);
	if (tcgetattr(fd, &ti) < 0) {
		fprintf(stderr, "Can't get port settings: %s (%d)\n", strerror(errno), errno);
		close(fd);
		fd = -1;
		return -1;
	}
	cfmakeraw(&ti);
	ti.c_cflag |=  CLOCAL;
	ti.c_cflag &= ~CRTSCTS;
	//ti.c_cflag |= CRTSCTS;
	//ti.c_cflag |= PARENB;
	ti.c_cflag |= IGNBRK;
	ti.c_cc[VMIN] = 1;
	ti.c_cc[VTIME] = 0;
	if (baud == 0)
		baud = B115200;
	cfsetospeed(&ti, baud);
	if (tcsetattr(fd, TCSANOW, &ti) < 0) {
		fprintf(stderr, "Can't change port settings: %s (%d)\n", strerror(errno), errno);
		close(fd);
		fd = -1;
		return -1;
	}
	tcflush(fd, TCIOFLUSH);
	if (fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK) < 0) {
		fprintf(stderr, "Can't set non blocking mode: %s (%d)\n", strerror(errno), errno);
		close(fd);
		fd = -1;
		return -1;
	}
	return 0;
}

int uart_get_fd(void)
{
	return fd;
}

void put_uart(uint8_t ch)
{
	if (write(fd, &ch, 1) < 0)
		fprintf(stderr, "UART write error\n");
}

void write_uart(char *buf, int size)
{
int remain = size;
int ret;

	do {
		ret = write(fd, buf, size);
		if (ret < 0)
			fprintf(stderr, "UART write error\n");
		remain -= ret;
		buf += ret;
	} while (remain && (ret>=0));
}

uint8_t get_uart(uint8_t *ch)
{
	int res = read(fd, ch, 1);
	return res > 0 ? res : 0;
}

int uart_read(char *rxbuf, int maxlen)
{
	return read(fd, rxbuf, maxlen);
}

void close_uart(void)
{
	close(fd);
	fd = -1;
}