[U-Boot-Users] MTD Concat support

[Luigi 'Comio' Mantellini]

Il giorno mer, 16/04/2008 alle 22.23 +0300, Vlad Lungu ha scritto:

> Luigi 'Comio' Mantellini wrote:
> [snip]
> > I have 2 identical flash chip from spansion. 
> >   
> Can you tell me the part number so I can do a quick check on it?


I'll send you the exact part number tomorrow.


> > Anyway, from my modest point of view, the u-boot flash memory model is
> > too rigid. I would like a "linux" model like this:
> >                          -----------
> >                          |         |-> [ MTD Driver ] -> Flash 1 (Nor)
> > ---> flash operation --> | MTD Mux |-> [ MTD Driver ] -> Flash 2 (Nand)
> >                          |         |-> [ MTD Driver ] -> Flash n (XXX)
> >                          -----------
> >   
> I don't think it works that way in Linux. The devices you're 
> concatenating must be basically the same (both nor or nand,
> same width, same sector size / OOB area size for NAND, etc ) . That's 
> what I understand after a quick read of the docs.
> 

Yes, you're right. I just proposed a different architecture that is not
implemented in U-boot :)


> > MTD Mus is itself a MTD Driver. This infrastructure could be implemented
> > using smart descriptor to keep the need callback.
> >   
> 
> You could easily do that, but you still need to have similar devices. 
> Anyway, we're talking about an embedded bootloader here, you put too 
> much stuff in it and it gets bigger than the actual application :-)
> 


I don't think that my proposed architecture is more complex than the
actual u-boot implementation. Anyway, to implement proposed idea, we
need a descriptor that keeps also the needed callbacks (like init,
getsize, writebuffer, ...) as well as needed information (address base,
bank number, ...). This architecture should permit to integrate and
create a single front-end for all mtd devices avoiding to replicate the
politics. Every mtd should define just the mechanisms and exports a
descriptor.

I think that these considerations are off-topic... but I prefer to share
my vision.

Thanks a lot,

luigi


> Vlad
> 


Ing. Luigi Mantellini
Industrie Dial Face S.p.A.
Via Canzo, 4 
20068 Peschiera Borromeo (MI)
Tel.: +39 02 5167 2813
Fax: +39 02 5167 2459
E-mail: luigi.mantellini at idf-hit.com


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