Messages in this thread | | | Date | Wed, 2 Nov 2022 14:14:00 +0100 | From | Miquel Raynal <> | Subject | Re: Barebox / Kernel Omap ECC inconsistency? |
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Hi Colin,
rogerq@kernel.org wrote on Wed, 2 Nov 2022 09:12:27 +0200:
> Hi Colin, > > On 01/11/2022 21:09, Colin Foster wrote: > > Hello, > > > > I'm trying to revive a product that runs on a Phytec OMAP 4460 SOM. I > > submitted a .dts RFC a month or so ago, and plan to perform the > > suggestions and resubmit, but I'm up against one main hurdle that seems > > to be related to flash OOB/ECC. (get_maintainers on > > drivers/mtd/nand/raw/omap2.c is how I got this email list) > > > > Barebox has "native" support for the Phytec SOM: > > https://git.pengutronix.de/cgit/barebox/tree/arch/arm/boards/phytec-phycore-omap4460 > > > > It seems like Barebox is writing and expecting ECC bits to start at an > > offset of 12 bytes, while the kernel (and Barebox comments suggest) the > > ECC bytes should start at 2. I'm seeing this with > > `nanddump -n -o -l 0x41000 -f mtdxnanddump /dev/mtdx` > > > > Barebox created partition with UBI (mtd3) > > ... > > 00000800 ff ff ff ff ff ff ff ff ff ff ff ff 56 49 fd 17 > > 00000810 b2 25 60 1a 42 1d eb 56 5d ff ff ff ff ff ff ff > > ... > > > > Kernel created partition with UBI (mtd4) > > ... > > 00000800 ff ff 07 73 04 ac 57 6b 9b 1f 92 49 ab e0 b9 ff > > 00000810 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff > > ... > > > > > > My question: > > > > Am I right to assume this is an issue in Barebox? Perhaps this is just a > > I'm guessing so. Both u-boot and Linux for OMAP put the ECC bytes right > after the Bad block marker which is 2 bytes.
Yep. I checked, this has been like that since at least 2014, I don't think we changed the layout in U-Boot/Linux "recently"... (I haven't checked earlier, by laziness).
> https://elixir.bootlin.com/linux/latest/source/drivers/mtd/nand/raw/omap2.c#L1729 > https://elixir.bootlin.com/linux/latest/source/drivers/mtd/nand/raw/omap2.c#L134 > > > bug that has been fairly dormant for 15 years. If that is the case, I > > assume there's probably no hope in getting this mainlined, and "native" > > barebox support is just a ruse. > > > > If that isn't the case, is there a hidden "shift OOB by 10" config > > option that I'm missing? Or am I interpreting this data incorrectly? > > > > > > Any suggestions would be greatly appreciated. > > You should fix the OMAP NAND driver/config in Barebox to match that > with Linux OMAP NAND driver if you want them to run on the same system.
Agreed.
Thanks, Miquèl
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