[U-Boot] Remove global variable env_t *env_ptr ?

[Wolfgang Denk]

Dear Joakim,

In message <1491302640.30240.1.camel at infinera.com> you wrote:
>
> > That is my exact question - when would this happen?  Flash sectors
> > do now wander around in memory or change size :-)
>
> No, but they happens when you are forced to update you HW with new type of flashes
> with different layout so you have to move where the environment is stored.
> Sure, this can be fixed by having two different u-boot images but that will
> in our case be just painful to carry around an extra u-boot img, then in field
> devise a method to chose the right img. for what looks like the same HW but the flash.

I see. Well, this obviously means that you are _not_ using an
embedded environment, as otherwise the linker generated image would
be wrong for the "other" type of flash chips - which means, the
environment is somewhare outside, separate from the U-Boot image.

So you have old hardware, running old U-Boot, which does not support
the new flash.  For this, you need a new U-Boot, which then shall
support both the old and the new flash, right?  But why can you then
not simply come up with a new flash layout, which is compatoble with
the old and new flashes, so it can use a common configuration,
without code changes?

I'm aware that embedded environment is not used very often these
days any more, as is parallel NOR flash, but changes in this are
have caused trouble more than once in the past, so I am not
convinced that it's wise to touch such ancient, "stable" code for
an exotic feature that probably nobody else will ever need?


Best regards,

Wolfgang Denk

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