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 */
  9static 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 * Check every day in specified number of years interval starting on 1970-01-01
 31 * against the expected result.
 32 */
 33static void rtc_time64_to_tm_test_date_range(struct kunit *test, int years)
 34{
 35	/*
 36	 * years	= (years / 400) * 400 years
 37	 *		= (years / 400) * 146097 days
 38	 *		= (years / 400) * 146097 * 86400 seconds
 39	 */
 40	time64_t total_secs = ((time64_t)years) / 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) : %lld", \
 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/*
 70 * Checks every day in a 160000 years interval starting on 1970-01-01
 71 * against the expected result.
 72 */
 73static void rtc_time64_to_tm_test_date_range_160000(struct kunit *test)
 74{
 75	rtc_time64_to_tm_test_date_range(test, 160000);
 76}
 77
 78/*
 79 * Checks every day in a 1000 years interval starting on 1970-01-01
 80 * against the expected result.
 81 */
 82static void rtc_time64_to_tm_test_date_range_1000(struct kunit *test)
 83{
 84	rtc_time64_to_tm_test_date_range(test, 1000);
 85}
 86
 87static struct kunit_case rtc_lib_test_cases[] = {
 88	KUNIT_CASE(rtc_time64_to_tm_test_date_range_1000),
 89	KUNIT_CASE_SLOW(rtc_time64_to_tm_test_date_range_160000),
 90	{}
 91};
 92
 93static struct kunit_suite rtc_lib_test_suite = {
 94	.name = "rtc_lib_test_cases",
 95	.test_cases = rtc_lib_test_cases,
 96};
 97
 98kunit_test_suite(rtc_lib_test_suite);
 99
100MODULE_DESCRIPTION("KUnit test for RTC lib functions");
101MODULE_LICENSE("GPL");