[U-Boot-Users] U-Boot and Nand Flash

Wolfgang Denk
2004-09-09T00:15:41Z

In message <963b3387040908144747363b14@mail.gmail.com> you wrote:
>
> Is Nand flash actually supported by U-Boot? I've been looking through

Yes, it is.

> the sources
> and could not find any references to Nand flash. I don't believe that
Nand flash is
> supported but wanted to make sure prior to jumping in.

Argh... Please look again. It's so obvious rthat I cannot imagine how
you missed it. Guess what all these things are about:

-> ls */*nand*
common/cmd_nand.c common/env_nand.c doc/README.nand

> Also, it seems like all of the code that would access flash, does it
> simply by reading
> from the address that the flash is located at. Although, this works
> for other flash
> types (ie. Intel Strataflash) this will not work for Nand flash.

Please look again.

> Would there be any objection to adding a read_flash function to the
> flash drivers
> so that the type of flash being used is generic?

Yes, there would be, as no such change is necessary. Everything is
working fine as is.

> The nand flash driver that I write will be cpu/ppc4xx/440ep_ndfc.c as the 440ep
> has a Nand Flash Controller on it in addition to the board/x/flash.c
> that contains
> the flash protection and serial reading code.

Make sure not to mix up CPU specific and generic code.

PLEASE CHECK FIRST WHAT ALREADY EXISTS, and TRY TO UNDERSTAND this code.

> I want to eventually get patches to all the work to get the board and processor
> working back into U-Boot so please let me know if I should be doing any of the
> above items in a different manner.

Yes. Please read the code first. I mean: _really_ read it.

Best regards,

Wolfgang Denk

--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de
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