[U-Boot] [PATCH 6/6] EA20: do not use subpage write for NAND

Stefano Babic
2011-04-15T17:34:48Z

On 04/13/2011 06:24 PM, Scott Wood wrote:

Hi Scott,

> Davinci-specific #defines do not belong in nand_base.c[1]. The controller
> driver should be able to set "this isn't supported" options just as well as
> the chip data -- I just don't think it should be limited to this specific
> one.

surely, but it is not clear to me how. There is no entry for a
write_subpage function, as this issue does not happen with other
controllers, and I do not see a callback for the driver after the
nand_scan() function, where I thought the driver could change the
options according to its capabilities.

>
> For example, fsl_elbc_nand.c sets NAND_NO_READRDY and NAND_NO_AUTOINCR.
> Before this thread, I didn't realize it they were getting ignored.
> Things
> work anyway because the former is an optimization, and the latter is getting
> forced on after the masking, for some reason -- does autoincr simply not
> work? Can we remove the code? :-)

Well, the options are simply ignored, I agree about removing them.

>
> -Scott
>
> [1] Nor should it be turned back into a non-davinci define -- what if there
> are multiple NAND controllers supported, and only one requires this? It's
> not so bad in U-Boot (I'd still rather avoid it though), but this approach
> is not going to go over well in Linux.
>
> How is Linux handling this?

What I have seen (kernel 2.6.38), the options are ignored in Linux as
well, and this issue is open for the davinci processors.

Best regards,
Stefano Babic

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