Re: Have fsl_elbc_nand controllers subpage write support?

Pali Rohár
2022-08-07T14:13:28Z

On Sunday 07 August 2022 14:00:27 Pali Rohár wrote:
> Hello Scott!
>
> In past you disabled nand subpage write support for freescale eLBC and
> IFC U-Boot nand drivers in following patch:
> https://lore.kernel.org/u-boot/20121102234432.GA18129@buserror.net/
>
> But in Linux kernel you disabled it only in freescale IFC nand driver:
> https://lore.kernel.org/linux-mtd/20130410223437.GA26900@home.buserror.net/
>
> letting kernel's freescale eLBC driver to have enabled subpage write
> support.
>
> I would like to ask, has freescale eLBC nand controller support for
> subpage writes? Or not and it should be disabled also in kernel?
>
> Or has somebody else these details?

Now I found following commit http://git.kernel.org/torvalds/c/f034d87def51
which seems to be fixing/emulating subpage write support.

> The main issue is that U-Boot nand and UBI support for boards with eLBC
> controllers is compatible with Linux kernel nand and UBI support because
> these two drivers calculate UBI geometry differently. UBI header offset
> is calculated from nand subpage size and nand subpage size obviously
> depends on the fact if subpage write is supported or not.
>
> I would like to fix this issue, but I do not know if wrong information
> is in U-Boot driver or in Linux kernel driver.