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dm: rtc: Try to handle the localtime() race

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At present the sandbox timer uses localtime() which can jump around twice
a year when daylight-saving time changes.

It would be tricky to make use of gmtime() since we still need to present
the time in local time, as seems to be required by U-Boot's RTC interface.

The problem can only happen once, so use a loop to detect it and try
again. This should be sufficient to detect either a change in the 'second'
value, or a daylight-saving change. We can assume that the latter also
incorporates a 'second' change, so there is no need to loop more than
twice.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2022-08-01 07:58:48 -06:00 committed by Tom Rini
parent fc7ceae0d5
commit 21ddac140e
1 changed files with 17 additions and 11 deletions
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20
test/dm/rtc.c
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@ -252,6 +252,7 @@ static int dm_test_rtc_reset(struct unit_test_state *uts)
struct rtc_time now;
struct udevice *dev, *emul;
long old_base_time, base_time;
int i;
ut_assertok(uclass_get_device(UCLASS_RTC, 0, &dev));
ut_assertok(dm_rtc_get(dev, &now));
@ -259,19 +260,24 @@ static int dm_test_rtc_reset(struct unit_test_state *uts)
ut_assertok(i2c_emul_find(dev, &emul));
ut_assertnonnull(emul);
i = 0;
do {
old_base_time = sandbox_i2c_rtc_get_set_base_time(emul, 0);
ut_asserteq(0, sandbox_i2c_rtc_get_set_base_time(emul, -1));
/*
* Resetting the RTC should put the base time back to normal. Allow for
* a one-second adjustment in case the time flips over while this
* test process is pre-empted, since reset_time() in i2c_rtc_emul.c
* reads the time from the OS.
*/
ut_assertok(dm_rtc_reset(dev));
base_time = sandbox_i2c_rtc_get_set_base_time(emul, -1);
ut_assert(base_time - old_base_time <= 1);
/*
* Resetting the RTC should put the base time back to normal.
* Allow for a one-timeadjustment in case the time flips over
* while this test process is pre-empted (either by a second
* or a daylight-saving change), since reset_time() in
* i2c_rtc_emul.c reads the time from the OS.
*/
} while (++i < 2 && base_time != old_base_time);
ut_asserteq(old_base_time, base_time);
return 0;
}