[PATCH v2] mtd: rawnand: sunxi: fit maximized ECC step to page size

[James Hilliard]

On Tue, Sep 8, 2026 at 4:03 AM Miquel Raynal <miquel.raynal at bootlin.com> wrote:
>
> Hello James,
>
> On 04/09/2026 at 16:39:27 -06, James Hilliard <james.hilliard1 at gmail.com> wrote:
>
> > When nand-ecc-maximize is set, the driver unconditionally selects a
> > 1024-byte ECC step. A NAND with a 512-byte page consequently produces
> > zero ECC steps before the available OOB bytes are divided by the step
> > count.
> >
> > The older sunxi NAND controllers support 512-byte ECC blocks. Select the
> > smaller of the page size and the preferred 1024-byte step, using a
> > 512-byte step for a 512-byte page while retaining 1024-byte steps for
> > larger pages. Unsupported smaller steps and controllers without
> > 512-byte support continue to be rejected by the existing checks.
> >
> > Fixes: 4796d8655915 ("mtd: nand: sunxi: Support ECC maximization")
> > Cc: stable at vger.kernel.org
> > Signed-off-by: James Hilliard <james.hilliard1 at gmail.com>
>
> As reported by Sashiko, there is another use of 1024 down the road which
> must be modified accordingly. Although, in practice, 512-byte page NANDs
> have disappeared for quite some time, so this is a theoretical fix more
> than a real problem.

Does the v3 I sent look like it should work?:
https://lore.kernel.org/all/20260904-submit-sunxi-nand-ecc-step-validation-v3-1-931cec317c10@gmail.com/

>
> Thanks,
> Miquèl