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/input.h>
32 #include <errno.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 #include <poll.h>
38 #include <sys/types.h>
39 #include <sys/ioctl.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 
43 #include "bpf_util.h"
44 #include <bpf/bpf.h>
45 #include <bpf/libbpf.h>
46 
47 #include "testing_helpers.h"
48 
49 int main(int argc, char **argv)
50 {
51 	struct bpf_object *obj;
52 	int ret, lircfd, progfd, inputfd;
53 	int testir1 = 0x1dead;
54 	int testir2 = 0x20101;
55 	u32 prog_ids[10], prog_flags[10], prog_cnt;
56 
57 	if (argc != 3) {
58 		printf("Usage: %s /dev/lircN /dev/input/eventM\n", argv[0]);
59 		return 2;
60 	}
61 
62 	ret = bpf_prog_test_load("test_lirc_mode2_kern.bpf.o",
63 				 BPF_PROG_TYPE_LIRC_MODE2, &obj, &progfd);
64 	if (ret) {
65 		printf("Failed to load bpf program\n");
66 		return 1;
67 	}
68 
69 	lircfd = open(argv[1], O_RDWR | O_NONBLOCK);
70 	if (lircfd == -1) {
71 		printf("failed to open lirc device %s: %m\n", argv[1]);
72 		return 1;
73 	}
74 
75 	/* Let's try detach it before it was ever attached */
76 	ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
77 	if (ret != -1 || errno != ENOENT) {
78 		printf("bpf_prog_detach2 not attached should fail: %m\n");
79 		return 1;
80 	}
81 
82 	inputfd = open(argv[2], O_RDONLY | O_NONBLOCK);
83 	if (inputfd == -1) {
84 		printf("failed to open input device %s: %m\n", argv[1]);
85 		return 1;
86 	}
87 
88 	prog_cnt = 10;
89 	ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
90 			     &prog_cnt);
91 	if (ret) {
92 		printf("Failed to query bpf programs on lirc device: %m\n");
93 		return 1;
94 	}
95 
96 	if (prog_cnt != 0) {
97 		printf("Expected nothing to be attached\n");
98 		return 1;
99 	}
100 
101 	ret = bpf_prog_attach(progfd, lircfd, BPF_LIRC_MODE2, 0);
102 	if (ret) {
103 		printf("Failed to attach bpf to lirc device: %m\n");
104 		return 1;
105 	}
106 
107 	/* Write raw IR */
108 	ret = write(lircfd, &testir1, sizeof(testir1));
109 	if (ret != sizeof(testir1)) {
110 		printf("Failed to send test IR message: %m\n");
111 		return 1;
112 	}
113 
114 	struct pollfd pfd = { .fd = inputfd, .events = POLLIN };
115 	struct input_event event;
116 
117 	for (;;) {
118 		poll(&pfd, 1, 100);
119 
120 		/* Read decoded IR */
121 		ret = read(inputfd, &event, sizeof(event));
122 		if (ret != sizeof(event)) {
123 			printf("Failed to read decoded IR: %m\n");
124 			return 1;
125 		}
126 
127 		if (event.type == EV_MSC && event.code == MSC_SCAN &&
128 		    event.value == 0xdead) {
129 			break;
130 		}
131 	}
132 
133 	/* Write raw IR */
134 	ret = write(lircfd, &testir2, sizeof(testir2));
135 	if (ret != sizeof(testir2)) {
136 		printf("Failed to send test IR message: %m\n");
137 		return 1;
138 	}
139 
140 	for (;;) {
141 		poll(&pfd, 1, 100);
142 
143 		/* Read decoded IR */
144 		ret = read(inputfd, &event, sizeof(event));
145 		if (ret != sizeof(event)) {
146 			printf("Failed to read decoded IR: %m\n");
147 			return 1;
148 		}
149 
150 		if (event.type == EV_REL && event.code == REL_Y &&
151 		    event.value == 1 ) {
152 			break;
153 		}
154 	}
155 
156 	prog_cnt = 10;
157 	ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
158 			     &prog_cnt);
159 	if (ret) {
160 		printf("Failed to query bpf programs on lirc device: %m\n");
161 		return 1;
162 	}
163 
164 	if (prog_cnt != 1) {
165 		printf("Expected one program to be attached\n");
166 		return 1;
167 	}
168 
169 	/* Let's try detaching it now it is actually attached */
170 	ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
171 	if (ret) {
172 		printf("bpf_prog_detach2: returned %m\n");
173 		return 1;
174 	}
175 
176 	return 0;
177 }
178