diff options
Diffstat (limited to 'src/core/serial.c')
| -rw-r--r-- | src/core/serial.c | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/src/core/serial.c b/src/core/serial.c new file mode 100644 index 00000000..117c049b --- /dev/null +++ b/src/core/serial.c @@ -0,0 +1,279 @@ +/*! \file serial.c + * Utility functions to deal with serial ports */ +/* + * Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com> + * + * All Rights Reserved + * + * SPDX-License-Identifier: GPL-2.0+ + * + * 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. + */ + +/*! \addtogroup serial + * @{ + * Osmocom serial port helpers + * + * \file serial.c */ + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <termios.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/stat.h> +#ifdef __linux__ +#include <linux/serial.h> +#endif + +#include <osmocom/core/serial.h> + + +#if 0 +# define dbg_perror(x) perror(x) +#else +# define dbg_perror(x) do { } while (0) +#endif + +/*! Open serial device and does base init + * \param[in] dev Path to the device node to open + * \param[in] baudrate Baudrate constant (speed_t: B9600, B...) + * \returns >=0 file descriptor in case of success or negative errno. + */ +int +osmo_serial_init(const char *dev, speed_t baudrate) +{ + int rc, fd=-1, v24, flags; + struct termios tio; + + /* Use nonblock as the device might block otherwise */ + fd = open(dev, O_RDWR | O_NOCTTY | O_SYNC | O_NONBLOCK); + if (fd < 0) { + dbg_perror("open"); + return -errno; + } + + /* now put it into blocking mode */ + flags = fcntl(fd, F_GETFL, 0); + if (flags < 0) { + dbg_perror("fcntl get flags"); + rc = -errno; + goto error; + } + + flags &= ~O_NONBLOCK; + rc = fcntl(fd, F_SETFL, flags); + if (rc != 0) { + dbg_perror("fcntl set flags"); + rc = -errno; + goto error; + } + + /* Configure serial interface */ + rc = tcgetattr(fd, &tio); + if (rc < 0) { + dbg_perror("tcgetattr()"); + rc = -errno; + goto error; + } + + if (cfsetispeed(&tio, baudrate) < 0) + dbg_perror("cfsetispeed()"); + if (cfsetospeed(&tio, baudrate) < 0) + dbg_perror("cfsetospeed()"); + + tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS); + tio.c_cflag |= (CREAD | CLOCAL | CS8); + tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); + tio.c_iflag |= (INPCK); + tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR); + tio.c_oflag &= ~(OPOST | ONLCR); + + rc = tcsetattr(fd, TCSANOW, &tio); + if (rc < 0) { + dbg_perror("tcsetattr()"); + rc = -errno; + goto error; + } + + /* Set ready to read/write */ + v24 = TIOCM_DTR | TIOCM_RTS; + rc = ioctl(fd, TIOCMBIS, &v24); + if (rc < 0) { + dbg_perror("ioctl(TIOCMBIS)"); + /* some serial porst don't support this, so let's not + * return an error here */ + } + + return fd; + +error: + if (fd >= 0) + close(fd); + return rc; +} + +static int +_osmo_serial_set_baudrate(int fd, speed_t baudrate) +{ + int rc; + struct termios tio; + + rc = tcgetattr(fd, &tio); + if (rc < 0) { + dbg_perror("tcgetattr()"); + return -errno; + } + + if (cfsetispeed(&tio, baudrate) < 0) + dbg_perror("cfsetispeed()"); + if (cfsetospeed(&tio, baudrate) < 0) + dbg_perror("cfsetospeed()"); + + rc = tcsetattr(fd, TCSANOW, &tio); + if (rc < 0) { + dbg_perror("tcsetattr()"); + return -errno; + } + + return 0; +} + +/*! Change current baudrate + * \param[in] fd File descriptor of the open device + * \param[in] baudrate Baudrate constant (speed_t: B9600, B...) + * \returns 0 for success or negative errno. + */ +int +osmo_serial_set_baudrate(int fd, speed_t baudrate) +{ + osmo_serial_clear_custom_baudrate(fd); + return _osmo_serial_set_baudrate(fd, baudrate); +} + +/*! Change current baudrate to a custom one using OS specific method + * \param[in] fd File descriptor of the open device + * \param[in] baudrate Baudrate as integer + * \returns 0 for success or negative errno. + * + * This function might not work on all OS or with all type of serial adapters + */ +int +osmo_serial_set_custom_baudrate(int fd, int baudrate) +{ +#ifdef __linux__ + int rc; + struct serial_struct ser_info; + + rc = ioctl(fd, TIOCGSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCGSERIAL)"); + return -errno; + } + + ser_info.flags = ASYNC_SPD_CUST | ASYNC_LOW_LATENCY; + ser_info.custom_divisor = ser_info.baud_base / baudrate; + + rc = ioctl(fd, TIOCSSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCSSERIAL)"); + return -errno; + } + + return _osmo_serial_set_baudrate(fd, B38400); /* 38400 is a kind of magic ... */ +#elif defined(__APPLE__) +#ifndef IOSSIOSPEED +#define IOSSIOSPEED _IOW('T', 2, speed_t) +#endif + int rc; + + unsigned int speed = baudrate; + rc = ioctl(fd, IOSSIOSPEED, &speed); + if (rc < 0) { + dbg_perror("ioctl(IOSSIOSPEED)"); + return -errno; + } + return 0; +#else +#pragma message ("osmo_serial_set_custom_baudrate: unsupported platform") + return 0; +#endif +} + +/*! Clear any custom baudrate + * \param[in] fd File descriptor of the open device + * \returns 0 for success or negative errno. + * + * This function might not work on all OS or with all type of serial adapters + */ +int +osmo_serial_clear_custom_baudrate(int fd) +{ +#ifdef __linux__ + int rc; + struct serial_struct ser_info; + + rc = ioctl(fd, TIOCGSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCGSERIAL)"); + return -errno; + } + + ser_info.flags = ASYNC_LOW_LATENCY; + ser_info.custom_divisor = 0; + + rc = ioctl(fd, TIOCSSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCSSERIAL)"); + return -errno; + } +#endif + return 0; +} + +/*! Convert unsigned integer value to speed_t + * \param[in] baudrate integer value containing the desired standard baudrate + * \param[out] speed the standrd baudrate requested in speed_t format + * \returns 0 for success or negative errno. + */ +int +osmo_serial_speed_t(unsigned int baudrate, speed_t *speed) +{ + switch(baudrate) { + case 0: *speed = B0; break; + case 50: *speed = B50; break; + case 75: *speed = B75; break; + case 110: *speed = B110; break; + case 134: *speed = B134; break; + case 150: *speed = B150; break; + case 200: *speed = B200; break; + case 300: *speed = B300; break; + case 600: *speed = B600; break; + case 1200: *speed = B1200; break; + case 1800: *speed = B1800; break; + case 2400: *speed = B2400; break; + case 4800: *speed = B4800; break; + case 9600: *speed = B9600; break; + case 19200: *speed = B19200; break; + case 38400: *speed = B38400; break; + case 57600: *speed = B57600; break; + case 115200: *speed = B115200; break; + case 230400: *speed = B230400; break; + default: + *speed = B0; + return -EINVAL; + } + return 0; +} + +/*! @} */ |