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author | Michal Simek <monstr@monstr.eu> | 2007-05-08 00:32:35 +0200 |
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committer | Michal Simek <monstr@monstr.eu> | 2007-05-08 00:32:35 +0200 |
commit | 3c4bd60de15d79ddfc0cf3170a55847b2025d93f (patch) | |
tree | 891b84b58f13a5f45536a243585b9d94c253a410 /doc/README.Lite5200B_low_power | |
parent | fb05f6da35ea1c15c553abe6f23f656bf18dc5db (diff) | |
parent | ac4cd59d59c9bf3f89cb7a344abf8184d678f562 (diff) | |
download | u-boot-imx-3c4bd60de15d79ddfc0cf3170a55847b2025d93f.zip u-boot-imx-3c4bd60de15d79ddfc0cf3170a55847b2025d93f.tar.gz u-boot-imx-3c4bd60de15d79ddfc0cf3170a55847b2025d93f.tar.bz2 |
Merge git://www.denx.de/git/u-boot
Conflicts:
include/asm-microblaze/microblaze_intc.h
include/linux/stat.h
Diffstat (limited to 'doc/README.Lite5200B_low_power')
-rw-r--r-- | doc/README.Lite5200B_low_power | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/doc/README.Lite5200B_low_power b/doc/README.Lite5200B_low_power new file mode 100644 index 0000000..5b04fbb --- /dev/null +++ b/doc/README.Lite5200B_low_power @@ -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. |