1 // SPDX-License-Identifier: LGPL-2.1+
2 
3 #include <kunit/test.h>
4 #include <linux/rtc.h>
5 
6 /*
7  * Advance a date by one day.
8  */
advance_date(int * year,int * month,int * mday,int * yday)9 static void advance_date(int *year, int *month, int *mday, int *yday)
10 {
11 	if (*mday != rtc_month_days(*month - 1, *year)) {
12 		++*mday;
13 		++*yday;
14 		return;
15 	}
16 
17 	*mday = 1;
18 	if (*month != 12) {
19 		++*month;
20 		++*yday;
21 		return;
22 	}
23 
24 	*month = 1;
25 	*yday  = 1;
26 	++*year;
27 }
28 
29 /*
30  * Checks every day in a 160000 years interval starting on 1970-01-01
31  * against the expected result.
32  */
rtc_time64_to_tm_test_date_range(struct kunit * test)33 static void rtc_time64_to_tm_test_date_range(struct kunit *test)
34 {
35 	/*
36 	 * 160000 years	= (160000 / 400) * 400 years
37 	 *		= (160000 / 400) * 146097 days
38 	 *		= (160000 / 400) * 146097 * 86400 seconds
39 	 */
40 	time64_t total_secs = ((time64_t) 160000) / 400 * 146097 * 86400;
41 
42 	int year	= 1970;
43 	int month	= 1;
44 	int mday	= 1;
45 	int yday	= 1;
46 
47 	struct rtc_time result;
48 	time64_t secs;
49 	s64 days;
50 
51 	for (secs = 0; secs <= total_secs; secs += 86400) {
52 
53 		rtc_time64_to_tm(secs, &result);
54 
55 		days = div_s64(secs, 86400);
56 
57 		#define FAIL_MSG "%d/%02d/%02d (%2d) : %ld", \
58 			year, month, mday, yday, days
59 
60 		KUNIT_ASSERT_EQ_MSG(test, year - 1900, result.tm_year, FAIL_MSG);
61 		KUNIT_ASSERT_EQ_MSG(test, month - 1, result.tm_mon, FAIL_MSG);
62 		KUNIT_ASSERT_EQ_MSG(test, mday, result.tm_mday, FAIL_MSG);
63 		KUNIT_ASSERT_EQ_MSG(test, yday, result.tm_yday, FAIL_MSG);
64 
65 		advance_date(&year, &month, &mday, &yday);
66 	}
67 }
68 
69 static struct kunit_case rtc_lib_test_cases[] = {
70 	KUNIT_CASE(rtc_time64_to_tm_test_date_range),
71 	{}
72 };
73 
74 static struct kunit_suite rtc_lib_test_suite = {
75 	.name = "rtc_lib_test_cases",
76 	.test_cases = rtc_lib_test_cases,
77 };
78 
79 kunit_test_suite(rtc_lib_test_suite);
80 
81 MODULE_LICENSE("GPL");
82