zephyr/subsys/modem/backends/modem_backend_tty.c

125 lines
3.3 KiB
C

/*
* Copyright (c) 2022 Trackunit Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/modem/backend/tty.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(modem_backend_tty);
#include <fcntl.h>
#include <unistd.h>
#include <poll.h>
#include <string.h>
#define MODEM_BACKEND_TTY_THREAD_PRIO (10)
#define MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS (1000)
#define MODEM_BACKEND_TTY_THREAD_POLL_DELAY (100)
#define MODEM_BACKEND_TTY_STATE_RUN_BIT (1)
static void modem_backend_tty_routine(void *p1, void *p2, void *p3)
{
struct modem_backend_tty *backend = (struct modem_backend_tty *)p1;
struct pollfd pd;
ARG_UNUSED(p2);
ARG_UNUSED(p3);
pd.fd = backend->tty_fd;
pd.events = POLLIN;
/* Run until run flag is cleared. Check every MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS */
while (atomic_test_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
/* Clear events */
pd.revents = 0;
if (poll(&pd, 1, MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS) < 0) {
LOG_ERR("Poll operation failed");
break;
}
if (pd.revents & POLLIN) {
modem_pipe_notify_receive_ready(&backend->pipe);
}
k_sleep(K_MSEC(MODEM_BACKEND_TTY_THREAD_POLL_DELAY));
}
}
static int modem_backend_tty_open(void *data)
{
struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
if (atomic_test_and_set_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
return -EALREADY;
}
backend->tty_fd = open(backend->tty_path, (O_RDWR | O_NONBLOCK), 0644);
if (backend->tty_fd < 0) {
return -EPERM;
}
k_thread_create(&backend->thread, backend->stack, backend->stack_size,
modem_backend_tty_routine, backend, NULL, NULL,
MODEM_BACKEND_TTY_THREAD_PRIO, 0, K_NO_WAIT);
modem_pipe_notify_opened(&backend->pipe);
return 0;
}
static int modem_backend_tty_transmit(void *data, const uint8_t *buf, size_t size)
{
struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
return write(backend->tty_fd, buf, size);
}
static int modem_backend_tty_receive(void *data, uint8_t *buf, size_t size)
{
int ret;
struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
ret = read(backend->tty_fd, buf, size);
return (ret < 0) ? 0 : ret;
}
static int modem_backend_tty_close(void *data)
{
struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
if (!atomic_test_and_clear_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
return -EALREADY;
}
k_thread_join(&backend->thread, K_MSEC(MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS * 2));
close(backend->tty_fd);
modem_pipe_notify_closed(&backend->pipe);
return 0;
}
struct modem_pipe_api modem_backend_tty_api = {
.open = modem_backend_tty_open,
.transmit = modem_backend_tty_transmit,
.receive = modem_backend_tty_receive,
.close = modem_backend_tty_close,
};
struct modem_pipe *modem_backend_tty_init(struct modem_backend_tty *backend,
const struct modem_backend_tty_config *config)
{
__ASSERT_NO_MSG(backend != NULL);
__ASSERT_NO_MSG(config != NULL);
__ASSERT_NO_MSG(config->tty_path != NULL);
memset(backend, 0x00, sizeof(*backend));
backend->tty_path = config->tty_path;
backend->stack = config->stack;
backend->stack_size = config->stack_size;
atomic_set(&backend->state, 0);
modem_pipe_init(&backend->pipe, backend, &modem_backend_tty_api);
return &backend->pipe;
}