[U-Boot-Users] [RFC] Complex MAPPING support on CFI driver

[Wolfgang Denk]

In message <200705231258.45889.rui.sousa at laposte.net> you wrote:
> 
> To support the flash one of our boards (no integrated in U-Boot) I need to 
> implement something similar to Linux MTD complex mappings option in the CFI 
> driver. In my case I have a NOR flash chip with an address line connected to 
> a GPIO pin. The GPIO pin needs to be set correctly at each access to the 
> flash.

I guess you lose... You probably can tweak U-Boot into thinking these
are different flash banks, but that's about all.

> Is  someone else already working on a solution?

Not that I know of.

> Would such a feature have a chance of being integrated in U-boot?

If a clean implementation was possible, yes, definitely. But I cannot
see how this could be done. We don;t have a driver  level  to  access
raw memory.

> Unfortunately this only takes care of writting operations. Support for read 

That's the main problem.

> would mean further extensive modifications (introduce some flash_read() 
> function and use it from cp, md, jffs2, ... commands).

And here it all breaks down. You cannot do this without messing with
lots of code.

The best you can probably do is provide a "bank switching" command to
select one of your banks.

Best regards,

Wolfgang Denk

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DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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Another megabytes the dust.