Signed-off-by: Domen Puncer <domen.puncer@telargo.com>master
parent
e673226ff9
commit
3747a3f010
@ -0,0 +1,22 @@ |
||||
Lite5200B wakeup from low-power mode (CONFIG_LITE5200B_PM) |
||||
---------------------------------------------------------- |
||||
|
||||
Low-power mode as described in Lite5200B User's Manual, means that |
||||
with support of MC68HLC908QT1 microcontroller (refered to as QT), |
||||
everything but the SDRAM can be powered down. This brings |
||||
maximum power saving, while one can still restore previous state |
||||
quickly. |
||||
|
||||
Quick overview where U-Boot comes into the picture: |
||||
- OS saves device states |
||||
- OS saves wakeup handler address to physical 0x0, puts SDRAM into |
||||
self-refresh and signals to QT, it should power down the board |
||||
- / board is sleeping here / |
||||
- someone presses SW4 (connected to QT) |
||||
- U-Boot checks PSC2_4 pin, if QT drives it down, then we woke up, |
||||
so get SDRAM out of self-refresh and transfer control to OS |
||||
wakeup handler |
||||
- OS restores device states |
||||
|
||||
This was tested on Linux with USB and Ethernet in use. Adding |
||||
support for other devices is an OS issue. |
Loading…
Reference in new issue