[U-Boot-Users] Altera Stratix II

[Wolfgang Denk]

In message <ffc2b1d40802291336s78a050b7i780fe48b9f2671ce at mail.gmail.com> you wrote:
>
> > I think what you're trying to do is fundamentally broken.  Why  don't
> > you  use  the  real sizes present on the hardware? Why do you want to
> > lie to yourself and to your users?
> 
> I have more then one way to answer this question some are more
> philosophical then others, But I will choose the bare hardware
> approach... we "hide" some backup information on the flash. We make
> sure the user can not access this hiden info by physically lifting the
> flash legs (there is a programmable part between the flash and the cpu
> on the bus). So though there may be a 64Mb flash the user really have
> a 32Mb. It is, in fact, the flash eeprom which lies to the u-boot /
> linux.

I see.

> Any attempt to access these non existing address will lead to bus
> fault exactly as if the flash was a 32Mb (which in many sense it is).
> So, again, it is important for me to tell u-boot "go ahaed and use
> CFI, but dont listen to the eeporm cuz he doesn't know what he is
> talking about".

I understand what you are trying to do, but I think  your  conclusion
is  wrong.  The  CFI  driver was implemented to read the geometry and
size information from the flash chips; if the  chips  cannot  provide
the  correct  information  (as in your case), they are simply not CFI
conformant, and you cannot use the CFI driver.

It may be possible to modify (or cripple) the CFI  driver  to  ignore
the information provided by the flash chips, or to overwrite parts of
this  information  (you  would  have  to  overwrite at least size and
number of sectors [and eventually the start address and first  sector
offset  if  you  map the flash at a fixed end address]) - but I don't
think that makes sense.

Best regards,

Wolfgang Denk

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