tree 0fe1da2d8e078eb5188dc30d536ea5bfd980db14
parent 1724b74f693812b48fa7e36e69174b271f3b5310
author Werner Zeh <werner.zeh@siemens.com> 1621945566 +0200
committer Patrick Georgi <pgeorgi@google.com> 1622406494 +0000

drivers/pc80/mc146818rtc: Check date and time for sanity

There are cases where the RTC_VRT bit in register D stays set after a
power failure while the real date and time registers can contain rubbish
values (can happen when RTC is not buffered). If we do not detect this
invalid date and/or time here and keep it, Linux will use these bad
values for the initial timekeeper init. This in turn can lead to dates
before 1970 in user land which can break a lot assumptions.

To fix this, check date and time sanity when the RTC is initialized and
reset the values if needed.

Change-Id: I5bc600c78bab50c70372600347f63156df127012
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54914
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>