1 // SPDX-License-Identifier: GPL-2.0
2 // test ir decoder
3 //
4 // Copyright (C) 2018 Sean Young <sean@mess.org>
5
6 // A lirc chardev is a device representing a consumer IR (cir) device which
7 // can receive infrared signals from remote control and/or transmit IR.
8 //
9 // IR is sent as a series of pulses and space somewhat like morse code. The
10 // BPF program can decode this into scancodes so that rc-core can translate
11 // this into input key codes using the rc keymap.
12 //
13 // This test works by sending IR over rc-loopback, so the IR is processed by
14 // BPF and then decoded into scancodes. The lirc chardev must be the one
15 // associated with rc-loopback, see the output of ir-keytable(1).
16 //
17 // The following CONFIG options must be enabled for the test to succeed:
18 // CONFIG_RC_CORE=y
19 // CONFIG_BPF_RAWIR_EVENT=y
20 // CONFIG_RC_LOOPBACK=y
21
22 // Steps:
23 // 1. Open the /dev/lircN device for rc-loopback (given on command line)
24 // 2. Attach bpf_lirc_mode2 program which decodes some IR.
25 // 3. Send some IR to the same IR device; since it is loopback, this will
26 // end up in the bpf program
27 // 4. bpf program should decode IR and report keycode
28 // 5. We can read keycode from same /dev/lirc device
29
30 #include <linux/bpf.h>
31 #include <linux/lirc.h>
32 #include <linux/input.h>
33 #include <errno.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <poll.h>
39 #include <sys/types.h>
40 #include <sys/ioctl.h>
41 #include <sys/stat.h>
42 #include <fcntl.h>
43
44 #include "bpf_util.h"
45 #include <bpf/bpf.h>
46 #include <bpf/libbpf.h>
47
main(int argc,char ** argv)48 int main(int argc, char **argv)
49 {
50 struct bpf_object *obj;
51 int ret, lircfd, progfd, inputfd;
52 int testir1 = 0x1dead;
53 int testir2 = 0x20101;
54 u32 prog_ids[10], prog_flags[10], prog_cnt;
55
56 if (argc != 3) {
57 printf("Usage: %s /dev/lircN /dev/input/eventM\n", argv[0]);
58 return 2;
59 }
60
61 ret = bpf_prog_load("test_lirc_mode2_kern.o",
62 BPF_PROG_TYPE_LIRC_MODE2, &obj, &progfd);
63 if (ret) {
64 printf("Failed to load bpf program\n");
65 return 1;
66 }
67
68 lircfd = open(argv[1], O_RDWR | O_NONBLOCK);
69 if (lircfd == -1) {
70 printf("failed to open lirc device %s: %m\n", argv[1]);
71 return 1;
72 }
73
74 /* Let's try detach it before it was ever attached */
75 ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
76 if (ret != -1 || errno != ENOENT) {
77 printf("bpf_prog_detach2 not attached should fail: %m\n");
78 return 1;
79 }
80
81 inputfd = open(argv[2], O_RDONLY | O_NONBLOCK);
82 if (inputfd == -1) {
83 printf("failed to open input device %s: %m\n", argv[1]);
84 return 1;
85 }
86
87 prog_cnt = 10;
88 ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
89 &prog_cnt);
90 if (ret) {
91 printf("Failed to query bpf programs on lirc device: %m\n");
92 return 1;
93 }
94
95 if (prog_cnt != 0) {
96 printf("Expected nothing to be attached\n");
97 return 1;
98 }
99
100 ret = bpf_prog_attach(progfd, lircfd, BPF_LIRC_MODE2, 0);
101 if (ret) {
102 printf("Failed to attach bpf to lirc device: %m\n");
103 return 1;
104 }
105
106 /* Write raw IR */
107 ret = write(lircfd, &testir1, sizeof(testir1));
108 if (ret != sizeof(testir1)) {
109 printf("Failed to send test IR message: %m\n");
110 return 1;
111 }
112
113 struct pollfd pfd = { .fd = inputfd, .events = POLLIN };
114 struct input_event event;
115
116 for (;;) {
117 poll(&pfd, 1, 100);
118
119 /* Read decoded IR */
120 ret = read(inputfd, &event, sizeof(event));
121 if (ret != sizeof(event)) {
122 printf("Failed to read decoded IR: %m\n");
123 return 1;
124 }
125
126 if (event.type == EV_MSC && event.code == MSC_SCAN &&
127 event.value == 0xdead) {
128 break;
129 }
130 }
131
132 /* Write raw IR */
133 ret = write(lircfd, &testir2, sizeof(testir2));
134 if (ret != sizeof(testir2)) {
135 printf("Failed to send test IR message: %m\n");
136 return 1;
137 }
138
139 for (;;) {
140 poll(&pfd, 1, 100);
141
142 /* Read decoded IR */
143 ret = read(inputfd, &event, sizeof(event));
144 if (ret != sizeof(event)) {
145 printf("Failed to read decoded IR: %m\n");
146 return 1;
147 }
148
149 if (event.type == EV_REL && event.code == REL_Y &&
150 event.value == 1 ) {
151 break;
152 }
153 }
154
155 prog_cnt = 10;
156 ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
157 &prog_cnt);
158 if (ret) {
159 printf("Failed to query bpf programs on lirc device: %m\n");
160 return 1;
161 }
162
163 if (prog_cnt != 1) {
164 printf("Expected one program to be attached\n");
165 return 1;
166 }
167
168 /* Let's try detaching it now it is actually attached */
169 ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
170 if (ret) {
171 printf("bpf_prog_detach2: returned %m\n");
172 return 1;
173 }
174
175 return 0;
176 }
177