Questions regarding JFFS2/NAND

[Josh Boyer]

On 9/25/06, Ajay Jain <ajain at neomagic.com> wrote:
>
> 1. Is it possible to run JFFS2 on NAND Flash on 2.4. I am seeing that
> the mtd website mentions that it is not supported. I do not clearly
> understand what it means. Does it mean that mtd guys do not support it,
> or does it mean that you can't run JFFS2 on nand in 2.4 at all.

The latter.  Unless you attempt to backport the code from 2.6.  And
that is definitely unsupported.

> 3. Because of this, we backported 'mtd' from 2.6 version. Now the mtd
> appears to be reasonably stable. But we still have the old jffs2 in
> place. The new mtd does not allow unaligned writes, but jffs2 (the old
> one) keeps sending unaligned requests. We modified the mtd layer to
> handle this, but then the issue is that we are writing to the same page
> again and again, as the writes are unaligned. But the ecc value can only
> be written once. So this solution will not work either. It does work if
> we switch off the ecc. Are you aware of any of these issues, is my
> observation correct.

You would need newer JFFS2.

> 4. Is it realistically possible to backport 2.6 JFFS2 to 2.4.

No, not really.

> Please help me to solve these issues. We want to run JFFS2 on 2.4/NAND.

http://linux-mtd.infradead.org/source.html#kernelversions

josh