1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Real Time Clock Periodic Interrupt test program |
4 | * |
5 | * Since commit 6610e0893b8bc ("RTC: Rework RTC code to use timerqueue for |
6 | * events"), PIE are completely handled using hrtimers, without actually using |
7 | * any underlying hardware RTC. |
8 | * |
9 | */ |
10 | |
11 | #include <stdio.h> |
12 | #include <linux/rtc.h> |
13 | #include <sys/ioctl.h> |
14 | #include <sys/time.h> |
15 | #include <sys/types.h> |
16 | #include <fcntl.h> |
17 | #include <unistd.h> |
18 | #include <stdlib.h> |
19 | #include <errno.h> |
20 | |
21 | #include "../kselftest.h" |
22 | |
23 | /* |
24 | * This expects the new RTC class driver framework, working with |
25 | * clocks that will often not be clones of what the PC-AT had. |
26 | * Use the command line to specify another RTC if you need one. |
27 | */ |
28 | static const char default_rtc[] = "/dev/rtc0" ; |
29 | |
30 | int main(int argc, char **argv) |
31 | { |
32 | int i, fd, retval, irqcount = 0; |
33 | unsigned long tmp, data, old_pie_rate; |
34 | const char *rtc = default_rtc; |
35 | struct timeval start, end, diff; |
36 | |
37 | switch (argc) { |
38 | case 2: |
39 | rtc = argv[1]; |
40 | break; |
41 | case 1: |
42 | fd = open(default_rtc, O_RDONLY); |
43 | if (fd == -1) { |
44 | printf("Default RTC %s does not exist. Test Skipped!\n" , default_rtc); |
45 | exit(KSFT_SKIP); |
46 | } |
47 | close(fd); |
48 | break; |
49 | default: |
50 | fprintf(stderr, "usage: rtctest [rtcdev] [d]\n" ); |
51 | return 1; |
52 | } |
53 | |
54 | fd = open(rtc, O_RDONLY); |
55 | |
56 | if (fd == -1) { |
57 | perror(rtc); |
58 | exit(errno); |
59 | } |
60 | |
61 | /* Read periodic IRQ rate */ |
62 | retval = ioctl(fd, RTC_IRQP_READ, &old_pie_rate); |
63 | if (retval == -1) { |
64 | /* not all RTCs support periodic IRQs */ |
65 | if (errno == EINVAL) { |
66 | fprintf(stderr, "\nNo periodic IRQ support\n" ); |
67 | goto done; |
68 | } |
69 | perror("RTC_IRQP_READ ioctl" ); |
70 | exit(errno); |
71 | } |
72 | fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n" , old_pie_rate); |
73 | |
74 | fprintf(stderr, "Counting 20 interrupts at:" ); |
75 | fflush(stderr); |
76 | |
77 | /* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */ |
78 | for (tmp=2; tmp<=64; tmp*=2) { |
79 | |
80 | retval = ioctl(fd, RTC_IRQP_SET, tmp); |
81 | if (retval == -1) { |
82 | /* not all RTCs can change their periodic IRQ rate */ |
83 | if (errno == EINVAL) { |
84 | fprintf(stderr, |
85 | "\n...Periodic IRQ rate is fixed\n" ); |
86 | goto done; |
87 | } |
88 | perror("RTC_IRQP_SET ioctl" ); |
89 | exit(errno); |
90 | } |
91 | |
92 | fprintf(stderr, "\n%ldHz:\t" , tmp); |
93 | fflush(stderr); |
94 | |
95 | /* Enable periodic interrupts */ |
96 | retval = ioctl(fd, RTC_PIE_ON, 0); |
97 | if (retval == -1) { |
98 | perror("RTC_PIE_ON ioctl" ); |
99 | exit(errno); |
100 | } |
101 | |
102 | for (i=1; i<21; i++) { |
103 | gettimeofday(&start, NULL); |
104 | /* This blocks */ |
105 | retval = read(fd, &data, sizeof(unsigned long)); |
106 | if (retval == -1) { |
107 | perror("read" ); |
108 | exit(errno); |
109 | } |
110 | gettimeofday(&end, NULL); |
111 | timersub(&end, &start, &diff); |
112 | if (diff.tv_sec > 0 || |
113 | diff.tv_usec > ((1000000L / tmp) * 1.10)) { |
114 | fprintf(stderr, "\nPIE delta error: %ld.%06ld should be close to 0.%06ld\n" , |
115 | diff.tv_sec, diff.tv_usec, |
116 | (1000000L / tmp)); |
117 | fflush(stdout); |
118 | exit(-1); |
119 | } |
120 | |
121 | fprintf(stderr, " %d" ,i); |
122 | fflush(stderr); |
123 | irqcount++; |
124 | } |
125 | |
126 | /* Disable periodic interrupts */ |
127 | retval = ioctl(fd, RTC_PIE_OFF, 0); |
128 | if (retval == -1) { |
129 | perror("RTC_PIE_OFF ioctl" ); |
130 | exit(errno); |
131 | } |
132 | } |
133 | |
134 | done: |
135 | ioctl(fd, RTC_IRQP_SET, old_pie_rate); |
136 | |
137 | fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n" ); |
138 | |
139 | close(fd); |
140 | |
141 | return 0; |
142 | } |
143 | |