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08609989 WBG |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Counter - example userspace application | |
3 | * | |
4 | * The userspace application opens /dev/counter0, configures the | |
5 | * COUNTER_EVENT_INDEX event channel 0 to gather Count 0 count and Count | |
6 | * 1 count, and prints out the data as it becomes available on the | |
7 | * character device node. | |
8 | * | |
9 | * Copyright (C) 2021 William Breathitt Gray | |
10 | */ | |
11 | #include <errno.h> | |
12 | #include <fcntl.h> | |
13 | #include <linux/counter.h> | |
14 | #include <stdio.h> | |
15 | #include <string.h> | |
16 | #include <sys/ioctl.h> | |
17 | #include <unistd.h> | |
18 | ||
19 | static struct counter_watch watches[2] = { | |
20 | { | |
21 | /* Component data: Count 0 count */ | |
22 | .component.type = COUNTER_COMPONENT_COUNT, | |
23 | .component.scope = COUNTER_SCOPE_COUNT, | |
24 | .component.parent = 0, | |
25 | /* Event type: Index */ | |
26 | .event = COUNTER_EVENT_INDEX, | |
27 | /* Device event channel 0 */ | |
28 | .channel = 0, | |
29 | }, | |
30 | { | |
31 | /* Component data: Count 1 count */ | |
32 | .component.type = COUNTER_COMPONENT_COUNT, | |
33 | .component.scope = COUNTER_SCOPE_COUNT, | |
34 | .component.parent = 1, | |
35 | /* Event type: Index */ | |
36 | .event = COUNTER_EVENT_INDEX, | |
37 | /* Device event channel 0 */ | |
38 | .channel = 0, | |
39 | }, | |
40 | }; | |
41 | ||
42 | int main(void) | |
43 | { | |
44 | int fd; | |
45 | int ret; | |
46 | int i; | |
47 | struct counter_event event_data[2]; | |
48 | ||
49 | fd = open("/dev/counter0", O_RDWR); | |
50 | if (fd == -1) { | |
51 | perror("Unable to open /dev/counter0"); | |
52 | return 1; | |
53 | } | |
54 | ||
55 | for (i = 0; i < 2; i++) { | |
56 | ret = ioctl(fd, COUNTER_ADD_WATCH_IOCTL, watches + i); | |
57 | if (ret == -1) { | |
58 | fprintf(stderr, "Error adding watches[%d]: %s\n", i, | |
59 | strerror(errno)); | |
60 | return 1; | |
61 | } | |
62 | } | |
63 | ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL); | |
64 | if (ret == -1) { | |
65 | perror("Error enabling events"); | |
66 | return 1; | |
67 | } | |
68 | ||
69 | for (;;) { | |
70 | ret = read(fd, event_data, sizeof(event_data)); | |
71 | if (ret == -1) { | |
72 | perror("Failed to read event data"); | |
73 | return 1; | |
74 | } | |
75 | ||
76 | if (ret != sizeof(event_data)) { | |
77 | fprintf(stderr, "Failed to read event data\n"); | |
78 | return -EIO; | |
79 | } | |
80 | ||
81 | printf("Timestamp 0: %llu\tCount 0: %llu\n" | |
82 | "Error Message 0: %s\n" | |
83 | "Timestamp 1: %llu\tCount 1: %llu\n" | |
84 | "Error Message 1: %s\n", | |
85 | event_data[0].timestamp, event_data[0].value, | |
86 | strerror(event_data[0].status), | |
87 | event_data[1].timestamp, event_data[1].value, | |
88 | strerror(event_data[1].status)); | |
89 | } | |
90 | ||
91 | return 0; | |
92 | } |