Re: [PATCH v1] mtd: spinand: micron: correct parameters

Martin Kurbanov
2023-08-21T17:36:48Z

Hi Miquel,

On 17.08.2023 10:53, Miquel Raynal wrote:
> It's not the first time we face this issue and the first approach we
> used was to "fix" the OOB layout to include all free bytes (not only
> protected bytes), which had the nice side-effect of allowing to write
> the cleanmarker in an ECC-free area and allow that chip to be used with
> JFFS2. This is indeed not a proper solution and I agree we should have
> a system-wide solution.
>
>> Also I wonder if JFFS2 should instead write the cleanmarker with ECC
>> being turned of explicitly.
> The real question is, why would you still want to use JFFS2 on
> SPI-NAND? UBI is meant for that. JFFS2 was designed with NORs in mind,
> it can be used on small NAND chips because UBI is a bit glutton wrt,
> but I doubt we still have "small" SPI-NANDs on the market which require
> JFFS2 anymore. Do we?

Unfortunately, we cannot use UBI because we have a small flash SPI-NAND
and we need a small partition.

> Anyhow, if people want JFFS2 on NANDs, I agree we should maybe change
> how JFFS2 works and force raw accesses when it comes to writing the
> cleanmarker, because there is no knowledge of what is ECC protected or
> not in the current OOB layouts. I however have no idea of the possible
> side-effects, I've never looked into JFFS2 so deeply.

Then I can prepare a patchset that will disable cleanamarkers on the
compile time.
And today I will send the second version of this patch without fixes
to the OOB area.

--
Best Regards,
Martin Kurbanov