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| author | Wolfgang Denk <wd@denx.de> | 2012-04-29 23:57:39 (GMT) |
|---|---|---|
| committer | Wolfgang Denk <wd@denx.de> | 2012-07-29 13:42:02 (GMT) |
| commit | 702e6014f15b307f144fa03ecaf83a8446c6802a (patch) | |
| tree | 8c9360248c257f52c1487d9e6cbba3f2dc38e294 /board/icecube/README.Lite5200B_low_power | |
| parent | 631fea8f2d70aa5eb7c49b33039971dfc61bba88 (diff) | |
| download | u-boot-702e6014f15b307f144fa03ecaf83a8446c6802a.tar.xz | |
doc: cleanup - move board READMEs into respective board directories
Also drop a few files referring to no longer / not yet supported
boards.
Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Kim Phillips <kim.phillips@freescale.com>
Cc: Andy Fleming <afleming@gmail.com>
Cc: Jason Jin <jason.jin@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Acked-by: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
Diffstat (limited to 'board/icecube/README.Lite5200B_low_power')
| -rw-r--r-- | board/icecube/README.Lite5200B_low_power | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/board/icecube/README.Lite5200B_low_power b/board/icecube/README.Lite5200B_low_power new file mode 100644 index 0000000..5b04fbb --- /dev/null +++ b/board/icecube/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. |