serial_linux.c

/*      SAM7Sisp - alternatywny bootloader dla mikrokontrolerw AT91SAM7

        (c) Tomasz Wlostowski 2006

        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.
*/


#include <stdio.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <asm/ioctls.h>
#include <string.h>
#include <termios.h>
#include <fcntl.h>

static int serial_fd;

void serial_set_dtr(int s) // pin 4
{
    unsigned int v;
    if (serial_fd < 0) return;
    ioctl(serial_fd, TIOCMGET, &v);
    if (s) v |= TIOCM_DTR; else v &= ~TIOCM_DTR;
    ioctl(serial_fd, TIOCMSET, &v);
}

int serial_open(char *dev_name, int speed)
{
    struct termios t;
    int fd;
    int spd;

    switch(speed)
    {
	case 115200: spd = B115200; break;
	case 57600:  spd = B57600;  break;
	case 38400:  spd = B38400;  break;
	case 19200:  spd = B19200;  break;
	case 9600:   spd = B9600;   break;
	default: return -2;
    }

    fd = open(dev_name, O_RDWR);

    if (fd<0)
	return -1;

    tcgetattr (fd, &t);
    t.c_iflag = IGNBRK | IGNPAR;
    t.c_oflag = t.c_lflag = t.c_line = 0;
    t.c_cflag = CS8 | CREAD |  CLOCAL | HUPCL | spd;
    tcsetattr (fd, TCSAFLUSH, &t);

    serial_fd = fd;
    return 0;
}

void serial_close(void)
{
    close(serial_fd);
}

int serial_write(char *data, int len)
{
#ifdef DEBUG
    int i;

    printf("WS: '");
    for (i=0; i<len; i++)
	printf("%c", data[i]);
    printf("'\n");
#endif /* DEBUG */

    return write(serial_fd, data, len);
}


int serial_read(char *data, int len)
{
    int nbytes = 0;

    while (len) {
	if (read(serial_fd, data, 1) == 1) {
	    len--; data++; nbytes++;
	}
    }

    return nbytes;
};

/* serial_read with timeout as seconds */
int serial_read_w_timeout(char *data, int len, unsigned int *timeout_s)
{
    int nbytes = 0;
    int select_ret;
    fd_set set;
    struct timeval tv;

    FD_ZERO(&set);
    FD_SET(serial_fd, &set);

    while (len) {
	tv.tv_sec = *timeout_s;
	tv.tv_usec = 0;

	select_ret = select(serial_fd + 1, &set, NULL, NULL, &tv);

	if (!select_ret) {
		/* Timeout */
		*timeout_s = 0;
		return 0;
	}
	if (read(serial_fd, data, 1) == 1) {
	    len--; data++; nbytes++;
	}
    }

    return nbytes;
};

void serial_write_byte(unsigned char b)
{
#ifdef DEBUG
    printf("WB: '%c'\n", b);
#endif /* DEBUG */

    write (serial_fd, &b, 1);
}

char serial_read_byte(void)
{
    char b;

    serial_read(&b, 1);
#ifdef DEBUG
    printf("%02x ", b);
#endif /* DEBUG */

    return b;

}

/* serial_read_byte with timeout as seconds */
char serial_read_byte_w_timeout(unsigned int *timeout_s)
{
    char b;

    serial_read_w_timeout(&b, 1, timeout_s);
#ifdef DEBUG
    printf("%02x ", b);
#endif /* DEBUG */

    return b;

}

int serial_data_avail(void)
{
    fd_set set;
    struct timeval tv;

    FD_ZERO(&set);
    FD_SET(serial_fd, &set);

    tv.tv_sec = 0;
    tv.tv_usec = 0;

    return select(serial_fd+1, &set, NULL, NULL, &tv) > 0;
}

unsigned int sys_get_clock_usec(void)
{
    struct timezone tz = {0, 0};
    struct timeval tv;

    gettimeofday(&tv, &tz);

    return tv.tv_usec + tv.tv_sec * 1000000;
}

void sys_delay(int msecs)
{
    usleep(msecs * 1000);
}

void serial_purge(void)
{
    while (serial_data_avail())
	serial_read_byte();
}