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authorWolfgang Denk <wd@denx.de>2012-04-29 23:57:39 (GMT)
committerWolfgang Denk <wd@denx.de>2012-07-29 13:42:02 (GMT)
commit702e6014f15b307f144fa03ecaf83a8446c6802a (patch)
tree8c9360248c257f52c1487d9e6cbba3f2dc38e294 /board/icecube/README.Lite5200B_low_power
parent631fea8f2d70aa5eb7c49b33039971dfc61bba88 (diff)
downloadu-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>
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+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.