RTC,system timer, android时间日期管理

Guess Android SystemClock keeps system timer and rtc count sync.

 

power on reset -> reserve rtc power only

command reboot (system software reset) -> reserve PM, RSC, RTC, GPIO

 

For keep time for situations as sleep/wakeup, command reboot, power on reset and power cut boot.

 

bakeup overflow_rtc in memory for sleep/wakeup situation.

bakeup overflow_rtc in pwrc_scratch_pad register for command reboot situation.

save overflow_rtc in flash for power on reset situation.

battery charging rtc should be involved for power cut boot situation.