Have fsl_elbc_nand controllers subpage write support?

[Pali Rohár]

Hello!

On Sunday 07 August 2022 16:13:00 Pali Rohár wrote:
> 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.

If there is not any objections I would send patch to U-boot eLBC nand
controller driver which would remove that NAND_NO_SUBPAGE_WRITE too. As
those subpage write functions are present also in U-Boot driver.

Any comments?

> > 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.