On Sun, Jun 26, 2022 at 2:02 AM Daniel Golle <dan...@makrotopia.org> wrote: > > On Sat, Jun 25, 2022 at 10:10:08AM +0200, Kegl Rohit wrote: > > Hello! > > > > Is it possible to store the environment inside a mtd partition when > > using a single qspi nand chip as storage? > > CONFIG_MTD_SPI_NAND=y > > > > The idea is to separate the NAND into two system A/B. > > [...] > > > > CONFIG_ENV_IS_IN_UBI will do badblock handling, but it would be a huge > > overhead to create an extra ubifs mtd partition only for the > > environment. > > Actually it's not. The overhead of allocating a UBI volume is minimal > and typical logical block sizes are small enough to not be complete > overkill for something like a U-Boot environment. >
For 1.Solution it is not a big overhead. But if i want to isolate a/b completely e.g. 3.Solution: mtdparts_nand0=2m(uboot),1m(env_ubi),8m(system_a),8m(system_b) system_a/b ubifs is completely isolated and environment and environment_redundant stored in addtional env_ubi. It looks like ubi needs at least 2mb @ 128kb eraseblocks for itself. So a lot of wasted space for e.g. 128kb environment. > > Has anyone already created the A/B system approach with the mtd spi > > nand interface and can give me some input? > > Maybe see here for inspiration: > https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=package/boot/uboot-mediatek/patches/410-add-linksys-e8450.patch;h=fde679f3863ccf2e22a3e1fd299963b66041a0b9;hb=HEAD#l403 > This seems to match my 1.Solution. system_a/b volumes are in same ubi mtd partition and are not really isolated.
