Messages in this thread | | | Date | Wed, 2 Nov 2022 08:28:25 -0700 | From | Colin Foster <> | Subject | Re: Barebox / Kernel Omap ECC inconsistency? |
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On Wed, Nov 02, 2022 at 02:14:00PM +0100, Miquel Raynal wrote: > 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.
Got it. Thanks a lot for the info Roger and Miquel. I think this should be pretty doable, and I'll venture down that path.
> > Thanks, > Miquèl
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