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