libpayload: Improve rtc functions

On Lenovo T500 the RTC readings where wrong, as RTC has
different encodings, depending on the statusB register.

Support BCD vs binary RTC format and AM/PM vs 24h RTC format.

Fixes wrong date and time on Lenovo 500.

Change-Id: Id773c33e228973e190a7e14c3d11979678b1a619
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/18498
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
This commit is contained in:
Patrick Rudolph
2017-02-25 09:56:53 +01:00
committed by Patrick Georgi
parent ef613b97cf
commit 9f3e734e5c
2 changed files with 41 additions and 9 deletions

View File

@ -130,6 +130,9 @@ static const char _pstruct(key)[] \
#define NVRAM_RTC_YEAR 9 /**< RTC Year offset in CMOS */
#define NVRAM_RTC_FREQ_SELECT 10 /**< RTC Update Status Register */
#define NVRAM_RTC_UIP 0x80
#define NVRAM_RTC_STATUSB 11 /**< RTC Status Register B */
#define NVRAM_RTC_FORMAT_24HOUR 0x02
#define NVRAM_RTC_FORMAT_BINARY 0x04
/** Broken down time structure */
struct tm {