mirror of https://gerrit.osmocom.org/libosmocore
244 lines
5.5 KiB
C
244 lines
5.5 KiB
C
/*! \file serial.c
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* Utility functions to deal with serial ports */
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/*
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* Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com>
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*
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* All Rights Reserved
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/*! \addtogroup serial
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* @{
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* Osmocom serial port helpers
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*
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* \file serial.c */
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <termios.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#ifdef __linux__
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#include <linux/serial.h>
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#endif
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#include <osmocom/core/serial.h>
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#if 0
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# define dbg_perror(x) perror(x)
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#else
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# define dbg_perror(x) do { } while (0)
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#endif
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/*! Open serial device and does base init
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* \param[in] dev Path to the device node to open
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* \param[in] baudrate Baudrate constant (speed_t: B9600, B...)
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* \returns >=0 file descriptor in case of success or negative errno.
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*/
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int
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osmo_serial_init(const char *dev, speed_t baudrate)
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{
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int rc, fd=-1, v24, flags;
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struct termios tio;
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/* Use nonblock as the device might block otherwise */
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fd = open(dev, O_RDWR | O_NOCTTY | O_SYNC | O_NONBLOCK);
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if (fd < 0) {
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dbg_perror("open");
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return -errno;
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}
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/* now put it into blcoking mode */
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flags = fcntl(fd, F_GETFL, 0);
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if (flags < 0) {
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dbg_perror("fcntl get flags");
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rc = -errno;
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goto error;
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}
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flags &= ~O_NONBLOCK;
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rc = fcntl(fd, F_SETFL, flags);
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if (rc != 0) {
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dbg_perror("fcntl set flags");
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rc = -errno;
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goto error;
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}
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/* Configure serial interface */
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rc = tcgetattr(fd, &tio);
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if (rc < 0) {
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dbg_perror("tcgetattr()");
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rc = -errno;
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goto error;
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}
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cfsetispeed(&tio, baudrate);
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cfsetospeed(&tio, baudrate);
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tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS);
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tio.c_cflag |= (CREAD | CLOCAL | CS8);
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tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
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tio.c_iflag |= (INPCK | ISTRIP);
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tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR);
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tio.c_oflag &= ~(OPOST | ONLCR);
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rc = tcsetattr(fd, TCSANOW, &tio);
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if (rc < 0) {
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dbg_perror("tcsetattr()");
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rc = -errno;
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goto error;
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}
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/* Set ready to read/write */
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v24 = TIOCM_DTR | TIOCM_RTS;
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rc = ioctl(fd, TIOCMBIS, &v24);
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if (rc < 0) {
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dbg_perror("ioctl(TIOCMBIS)");
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/* some serial porst don't support this, so let's not
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* return an error here */
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}
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return fd;
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error:
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if (fd >= 0)
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close(fd);
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return rc;
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}
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static int
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_osmo_serial_set_baudrate(int fd, speed_t baudrate)
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{
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int rc;
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struct termios tio;
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rc = tcgetattr(fd, &tio);
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if (rc < 0) {
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dbg_perror("tcgetattr()");
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return -errno;
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}
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cfsetispeed(&tio, baudrate);
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cfsetospeed(&tio, baudrate);
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rc = tcsetattr(fd, TCSANOW, &tio);
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if (rc < 0) {
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dbg_perror("tcgetattr()");
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return -errno;
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}
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return 0;
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}
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/*! Change current baudrate
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* \param[in] fd File descriptor of the open device
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* \param[in] baudrate Baudrate constant (speed_t: B9600, B...)
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* \returns 0 for success or negative errno.
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*/
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int
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osmo_serial_set_baudrate(int fd, speed_t baudrate)
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{
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osmo_serial_clear_custom_baudrate(fd);
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return _osmo_serial_set_baudrate(fd, baudrate);
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}
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/*! Change current baudrate to a custom one using OS specific method
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* \param[in] fd File descriptor of the open device
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* \param[in] baudrate Baudrate as integer
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* \returns 0 for success or negative errno.
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*
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* This function might not work on all OS or with all type of serial adapters
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*/
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int
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osmo_serial_set_custom_baudrate(int fd, int baudrate)
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{
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#ifdef __linux__
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int rc;
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struct serial_struct ser_info;
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rc = ioctl(fd, TIOCGSERIAL, &ser_info);
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if (rc < 0) {
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dbg_perror("ioctl(TIOCGSERIAL)");
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return -errno;
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}
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ser_info.flags = ASYNC_SPD_CUST | ASYNC_LOW_LATENCY;
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ser_info.custom_divisor = ser_info.baud_base / baudrate;
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rc = ioctl(fd, TIOCSSERIAL, &ser_info);
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if (rc < 0) {
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dbg_perror("ioctl(TIOCSSERIAL)");
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return -errno;
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}
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return _osmo_serial_set_baudrate(fd, B38400); /* 38400 is a kind of magic ... */
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#elif defined(__APPLE__)
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#ifndef IOSSIOSPEED
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#define IOSSIOSPEED _IOW('T', 2, speed_t)
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#endif
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int rc;
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unsigned int speed = baudrate;
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rc = ioctl(fd, IOSSIOSPEED, &speed);
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if (rc < 0) {
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dbg_perror("ioctl(IOSSIOSPEED)");
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return -errno;
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}
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return 0;
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#else
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#pragma message ("osmo_serial_set_custom_baudrate: unsupported platform")
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return 0;
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#endif
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}
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/*! Clear any custom baudrate
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* \param[in] fd File descriptor of the open device
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* \returns 0 for success or negative errno.
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*
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* This function might not work on all OS or with all type of serial adapters
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*/
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int
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osmo_serial_clear_custom_baudrate(int fd)
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{
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#ifdef __linux__
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int rc;
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struct serial_struct ser_info;
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rc = ioctl(fd, TIOCGSERIAL, &ser_info);
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if (rc < 0) {
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dbg_perror("ioctl(TIOCGSERIAL)");
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return -errno;
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}
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ser_info.flags = ASYNC_LOW_LATENCY;
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ser_info.custom_divisor = 0;
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rc = ioctl(fd, TIOCSSERIAL, &ser_info);
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if (rc < 0) {
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dbg_perror("ioctl(TIOCSSERIAL)");
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return -errno;
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}
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#endif
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return 0;
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}
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/*! @} */
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