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

[Stefano Babic]

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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