271 lines
5.7 KiB
C
271 lines
5.7 KiB
C
/* T-Link interface using POSIX serial port */
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/* (C) 2008-2011 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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*
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* Authors: Harald Welte <laforge@gnumonks.org>
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* Pablo Neira Ayuso <pablo@gnumonks.org>
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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
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <termios.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <osmocom/core/select.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/core/talloc.h>
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#include <osmocom/core/timer.h>
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struct osmo_rs232 {
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struct osmo_fd ofd;
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struct llist_head tx_queue;
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struct {
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int (*read)(struct osmo_rs232 *);
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} cb;
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/* sometimes we want to delay the transmission. */
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struct osmo_timer_list tx_timer;
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struct {
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char serial_port[PATH_MAX];
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int baudrate;
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unsigned int delay_us;
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} cfg;
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};
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void rs232_tx_timer_cb(void *ptr)
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{
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struct osmo_rs232 *r = ptr;
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/* we're again ready to transmit. */
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osmo_fd_write_enable(&r->ofd);
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}
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static int handle_ser_write(struct osmo_fd *bfd)
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{
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struct osmo_rs232 *r = bfd->data;
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struct llist_head *lh;
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struct msgb *msg;
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int written;
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LOGP(DLINP, LOGL_DEBUG, "writing data to rs232\n");
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if (llist_empty(&r->tx_queue)) {
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osmo_fd_write_disable(&r->ofd);
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return 0;
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}
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lh = r->tx_queue.next;
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llist_del(lh);
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msg = llist_entry(lh, struct msgb, list);
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written = write(bfd->fd, msg->data, msg->len);
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if (written < msg->len) {
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LOGP(DLINP, LOGL_ERROR, "rs232: short write\n");
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msgb_free(msg);
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return -1;
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}
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msgb_free(msg);
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/* We've got more data to write, but we have to wait to make it. */
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if (!llist_empty(&r->tx_queue) && r->cfg.delay_us) {
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osmo_fd_write_disable(&r->ofd);
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osmo_timer_schedule(&r->tx_timer, 0, r->cfg.delay_us);
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}
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return 0;
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}
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static int handle_ser_read(struct osmo_fd *bfd)
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{
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struct osmo_rs232 *r = bfd->data;
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LOGP(DLINP, LOGL_DEBUG, "data to be read in rs232\n");
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if (r->cb.read)
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r->cb.read(r);
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return 0;
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}
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static int serial_fd_cb(struct osmo_fd *bfd, unsigned int what)
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{
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int rc = 0;
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if (what & OSMO_FD_READ)
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rc = handle_ser_read(bfd);
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if (rc < 0)
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return rc;
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if (what & OSMO_FD_WRITE)
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rc = handle_ser_write(bfd);
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return rc;
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}
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struct osmo_rs232 *osmo_rs232_create(void *ctx)
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{
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struct osmo_rs232 *r;
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r = talloc_zero(ctx, struct osmo_rs232);
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if (r == NULL)
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return NULL;
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INIT_LLIST_HEAD(&r->tx_queue);
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return r;
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}
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void osmo_rs232_set_serial_port(struct osmo_rs232 *r, char *serial_port)
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{
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osmo_strlcpy(r->cfg.serial_port, serial_port, PATH_MAX);
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}
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void osmo_rs232_set_baudrate(struct osmo_rs232 *r, int baudrate)
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{
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r->cfg.baudrate = baudrate;
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}
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void osmo_rs232_set_delay_us(struct osmo_rs232 *r, int delay_us)
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{
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r->cfg.delay_us = delay_us;
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}
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void osmo_rs232_set_read_cb(struct osmo_rs232 *r,
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int (*read_cb)(struct osmo_rs232 *r))
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{
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r->cb.read = read_cb;
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}
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/* XXX: Better use TIOCGSERIAL / TIOCSSERIAL to allow setting non-standard. */
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static struct baudrate2termbits {
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int rate;
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int def;
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} baudrate2termbits[] = {
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{ 9600, B9600 },
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{ 19200, B19200 },
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{ 38400, B38400 },
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{ 115200, B115200 },
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{ -1, -1 },
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};
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int osmo_rs232_open(struct osmo_rs232 *r)
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{
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int rc, i, speed = 0;
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struct osmo_fd *bfd = &r->ofd;
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struct termios tio;
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rc = open(r->cfg.serial_port, O_RDWR);
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if (rc < 0) {
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LOGP(DLINP, LOGL_ERROR, "rs232: cannot open serial port: %s",
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strerror(errno));
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return rc;
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}
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bfd->fd = rc;
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/* set baudrate */
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rc = tcgetattr(bfd->fd, &tio);
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if (rc < 0) {
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LOGP(DLINP, LOGL_ERROR, "rs232: tcgetattr says: %s",
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strerror(errno));
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return rc;
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}
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for (i=0; i<baudrate2termbits[i].rate; i++) {
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if (baudrate2termbits[i].rate == -1)
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break;
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if (baudrate2termbits[i].rate == r->cfg.baudrate) {
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speed = baudrate2termbits[i].def;
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break;
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}
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}
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if (speed == 0) {
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close(rc);
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bfd->fd = -1;
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return -1;
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}
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cfsetispeed(&tio, speed);
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cfsetospeed(&tio, speed);
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tio.c_cflag |= (CREAD | CLOCAL | CS8);
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tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS);
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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);
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rc = tcsetattr(bfd->fd, TCSADRAIN, &tio);
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if (rc < 0) {
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LOGP(DLINP, LOGL_ERROR, "rs232: tcsetattr says: %s",
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strerror(errno));
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return rc;
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}
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osmo_fd_setup(bfd, bfd->fd, OSMO_FD_READ, serial_fd_cb, r, 0);
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rc = osmo_fd_register(bfd);
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if (rc < 0) {
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close(bfd->fd);
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LOGP(DLINP, LOGL_ERROR, "rs232: could not register FD: %s\n",
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strerror(-rc));
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return rc;
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}
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if (r->cfg.delay_us)
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osmo_timer_setup(&r->tx_timer, rs232_tx_timer_cb, r);
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return 0;
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}
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int osmo_rs232_read(struct osmo_rs232 *r, struct msgb *msg)
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{
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int ret;
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ret = read(r->ofd.fd, msg->data, msg->data_len);
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if (ret < 0) {
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LOGP(DLINP, LOGL_ERROR, "read error: %s\n", strerror(errno));
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return -EIO;
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}
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msgb_put(msg, ret);
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return ret;
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}
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void osmo_rs232_write(struct osmo_rs232 *r, struct msgb *msg)
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{
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msgb_enqueue(&r->tx_queue, msg);
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osmo_fd_write_enable(&r->ofd);
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}
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void osmo_rs232_close(struct osmo_rs232 *r)
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{
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close(r->ofd.fd);
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r->ofd.fd = -1;
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}
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void osmo_rs232_destroy(struct osmo_rs232 *r)
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{
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talloc_free(r);
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}
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