drivers/rtc/lib_test.c

   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  */
   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  */
  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");