#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <linux/termios.h>
#include <unistd.h>
#include "debug.h"

/*
 * HACK: declare the ioctl function by hand...
 *
 * We cannot include <sys/ioctl.h> as it will eventually include
 * <termios.h>, which will conflict with <linux/temios.h>. As we
 * really need the latter one AND the ioctl, just declare it by hand
 * here so that we get to use it...
 */
int ioctl(int d, int request, ...);

/**
 * Open a serial device and adjust the baud rate to give (arbitrary)
 * baud rate. The actual baud rate is stored back to the @baud
 * variable. This might differ from the requested one as the
 * underlying hardware may not support all possible baud
 * rates.
 *
 * Returns the file descriptor that was opened.
 */
int open_at_baud(const char *device, int *baud)
{
	struct termios2 tios;
	int fd;

	fd = open(device, O_RDWR | O_NOCTTY | O_NDELAY);

	if (fd == -1) {
		pr_err("error opening %s: %m\n", device);
		return fd;
	}

	if (ioctl(fd, TCGETS2, &tios)) {
		pr_err("TCGETS2: %m\n");
		goto err;
	}

	tios.c_cflag &= ~CBAUD;
	tios.c_cflag |= BOTHER;
	tios.c_ispeed = *baud;
	tios.c_ospeed = *baud;

	if (ioctl(fd, TCSETS2, &tios)) {
		pr_err("TCSETS2: %m");
		goto err;
	}

	if (ioctl(fd, TCGETS2, &tios)) {
		pr_err("TCGETS2: %m");
		goto err;
	}

	*baud = tios.c_ospeed;

	return fd;
err:
	close(fd);

	return -1;
}