Re: [PATCH 0/3] mtd: Ingenic NAND fix for JZ4740

[Paul Cercueil]

Hi Nikolaus,

Le dim., nov. 7 2021 at 14:47:43 +0100, H. Nikolaus Schaller 
<hns@xxxxxxxxxxxxx> a écrit :
> Hi Paul,
>
> >  Am 09.10.2021 um 20:49 schrieb Paul Cercueil <paul@xxxxxxxxxxxxxxx>:
> >
> >  Hi,
> >
> >  Looks like NAND support has been broken on the JZ4740 SoC for a 
> > while;
>
> Yes, I remember someone telling that something was fundamentally 
> broken
> and impossible to be fixed a while ago.

You mean MLC NAND, and that's still broken.

> >  it looks like it comes from the fact that the "hw_oob_first" 
> > mechanism
> >  was dropped from the NAND core and moved to the Davinci driver.
> >
> >  It turns out the JZ4740 SoC needs it too; I didn't notice it when
> >  writing the new ingenic-nand driver (to replace the old jz4740-nand
> >  driver) most likely because my Device Tree had the "nand-ecc-mode" 
> > set
> >  to "hw_oob_first".
> >
> >  I am not very sure about patch [1/3]; to me the original code does 
> > not
> >  make sense, and it didn't work out-of-the-box on the JZ4740 without 
> > it.
> >  By applying patch [1/3] the function 
> > nand_read_page_hwecc_oob_first()
> >  can be reused for the JZ4740 SoC as well. But I did not test patch 
> > [1/3]
> >  on Davinci.
>
> would this also work for jz4780 NAND?

The JZ4780 NAND driver does work, but UBI refuses to use the CI20's 
NAND as it's a MLC.

-Paul