Re: [PATCH v1 4/5] mtd: rawnand: meson: clear OOB buffer before read

Arseniy Krasnov
2023-05-04T11:45:11Z

On 03.05.2023 22:48, Richard Weinberger wrote:
> Sorry for joining the party late.
>
> On Wed, May 3, 2023 at 10:07 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>>> So for me main question here is:
>>>
>>> How JFFS2 should work with controllers where we can't update data and OOB
>>> independently? Driver of this filesystem knows nothing about this features of
>>> the controller.
>>>
>>> Or JFFS2 works incorrectly in my case when it tries to call write page callback
>>> after calling write OOB callback (IIUC it is better to ask Richard as You mentioned above).
>>>
>>> Or may be it is better to suppress OOB write callback (or set it to NULL) in this
>>> driver as in vendor's driver?
>>
>> I would assume using the unprotected free OOB bytes to store the
>> cleanmarkers should work. But that's a bit fragile and very filesystem
>> oriented. I don't like this much. But on the other side JFFS2 is
>> legacy, you should use UBI (which does not play with OOB areas) :-)
>
> Please note that JFFS2's main use case is NOR flash. Support for NAND
> flash was never
> considered as fully complete/stable. That's why UBIFS (JFFS3 in the
> very beginning)
> was invented.

Hello Richard!

Thanks for this details! But I think it will be useful to make JFFS2 work correctly
on this chip :) Anyway i think it is not rare/exotic case to use JFFS2 on NAND.

Thanks, Arseniy

>
> Thanks,
> //richard