Bjørn Mork b2e810f495 kernel: ubootenv-nvram: driver for RAM backed environments ... The vendor U-Boot implementaion on Telenor branded ZyXEL EX5700 devices does not store its environment on flash. It is instead kept in a memory region. This is persistent over reboots, but not over power cycling. The dual partition failsafe system used by the vendor U-Boot requires the OS to modify a variable in this memory environment. This driver allows the ordinary uboot-envtools to access a memory region like it was a partition on NOR flash. The specific vendor U-Boot adds a "no-map" /reserved-memory section and a top level /ubootenv node pointing to the memory environment. The driver uses this device specific fact to locate the region. The matching and probing code will likely have to be adjusted for any other devices to be supported. Example partial device tree: / { .. ubootenv { memory-region = <&uenv>; compatible = "ubootenv"; }; .. reserved-memory { .. uenv: ubootenv@7ffe8000 { no-map; reg = <0 0x7ffe8000 0 0x4000>; }; Signed-off-by: Bjørn Mork <bjorn@mork.no>		2023-08-20 01:14:06 +02:00
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Makefile
ubootenv-nvram.c