1 /*
2 * Copyright (c) 2022 Trackunit Corporation
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/modem/backend/tty.h>
8
9 #include <zephyr/logging/log.h>
10 LOG_MODULE_REGISTER(modem_backend_tty, CONFIG_MODEM_MODULES_LOG_LEVEL);
11
12 #include <fcntl.h>
13 #include <unistd.h>
14 #include <poll.h>
15 #include <string.h>
16
17 #define MODEM_BACKEND_TTY_THREAD_PRIO (10)
18 #define MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS (1000)
19 #define MODEM_BACKEND_TTY_THREAD_POLL_DELAY (100)
20
21 #define MODEM_BACKEND_TTY_STATE_RUN_BIT (1)
22
modem_backend_tty_routine(void * p1,void * p2,void * p3)23 static void modem_backend_tty_routine(void *p1, void *p2, void *p3)
24 {
25 struct modem_backend_tty *backend = (struct modem_backend_tty *)p1;
26 struct pollfd pd;
27
28 ARG_UNUSED(p2);
29 ARG_UNUSED(p3);
30
31 pd.fd = backend->tty_fd;
32 pd.events = POLLIN;
33
34 /* Run until run flag is cleared. Check every MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS */
35 while (atomic_test_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
36 /* Clear events */
37 pd.revents = 0;
38
39 if (poll(&pd, 1, MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS) < 0) {
40 LOG_ERR("Poll operation failed");
41 break;
42 }
43
44 if (pd.revents & POLLIN) {
45 modem_pipe_notify_receive_ready(&backend->pipe);
46 }
47
48 k_sleep(K_MSEC(MODEM_BACKEND_TTY_THREAD_POLL_DELAY));
49 }
50 }
51
modem_backend_tty_open(void * data)52 static int modem_backend_tty_open(void *data)
53 {
54 struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
55
56 if (atomic_test_and_set_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
57 return -EALREADY;
58 }
59
60 backend->tty_fd = open(backend->tty_path, (O_RDWR | O_NONBLOCK), 0644);
61 if (backend->tty_fd < 0) {
62 return -EPERM;
63 }
64
65 k_thread_create(&backend->thread, backend->stack, backend->stack_size,
66 modem_backend_tty_routine, backend, NULL, NULL,
67 MODEM_BACKEND_TTY_THREAD_PRIO, 0, K_NO_WAIT);
68
69 modem_pipe_notify_opened(&backend->pipe);
70 return 0;
71 }
72
modem_backend_tty_transmit(void * data,const uint8_t * buf,size_t size)73 static int modem_backend_tty_transmit(void *data, const uint8_t *buf, size_t size)
74 {
75 struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
76 int ret;
77
78 ret = write(backend->tty_fd, buf, size);
79 modem_pipe_notify_transmit_idle(&backend->pipe);
80 return ret;
81 }
82
modem_backend_tty_receive(void * data,uint8_t * buf,size_t size)83 static int modem_backend_tty_receive(void *data, uint8_t *buf, size_t size)
84 {
85 int ret;
86 struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
87
88 ret = read(backend->tty_fd, buf, size);
89 return (ret < 0) ? 0 : ret;
90 }
91
modem_backend_tty_close(void * data)92 static int modem_backend_tty_close(void *data)
93 {
94 struct modem_backend_tty *backend = (struct modem_backend_tty *)data;
95
96 if (!atomic_test_and_clear_bit(&backend->state, MODEM_BACKEND_TTY_STATE_RUN_BIT)) {
97 return -EALREADY;
98 }
99
100 k_thread_join(&backend->thread, K_MSEC(MODEM_BACKEND_TTY_THREAD_RUN_PERIOD_MS * 2));
101 close(backend->tty_fd);
102 modem_pipe_notify_closed(&backend->pipe);
103 return 0;
104 }
105
106 static const struct modem_pipe_api modem_backend_tty_api = {
107 .open = modem_backend_tty_open,
108 .transmit = modem_backend_tty_transmit,
109 .receive = modem_backend_tty_receive,
110 .close = modem_backend_tty_close,
111 };
112
modem_backend_tty_init(struct modem_backend_tty * backend,const struct modem_backend_tty_config * config)113 struct modem_pipe *modem_backend_tty_init(struct modem_backend_tty *backend,
114 const struct modem_backend_tty_config *config)
115 {
116 __ASSERT_NO_MSG(backend != NULL);
117 __ASSERT_NO_MSG(config != NULL);
118 __ASSERT_NO_MSG(config->tty_path != NULL);
119
120 memset(backend, 0x00, sizeof(*backend));
121 backend->tty_path = config->tty_path;
122 backend->stack = config->stack;
123 backend->stack_size = config->stack_size;
124 atomic_set(&backend->state, 0);
125 modem_pipe_init(&backend->pipe, backend, &modem_backend_tty_api);
126 return &backend->pipe;
127 }
128
