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