[U-Boot-Users] Re: FT u-boot shim

Pantelis Antoniou
2006-04-27T21:25:41Z

On Thursday 27 April 2006 23:40, Jerry Van Baren wrote:
> Wolfgang Denk wrote:
> > In message <44511C88.1010107@smiths-aerospace.com> you wrote:
> >> A thought that keeps recurring (but I've suppressed because I don't have
> >> time to play...) is that it would be Really Cool[tm] to store the u-boot
> >> env variables in a flat tree and then pass the env/tree to linux. It
> >
> > If somebody wants to read the environment variables, you don't need
> > to create a flat tree from it.
>
> Understood. That is why it is Really Cool[tm] rather than Really
> Useful[tm] ;-)
>
> > Also, it doesn't solve the original problem as most of the informa-
> > tion you need to pass is NOT part of the environment (and shall not
> > become such a part).
> >
> > Best regards,
> > Wolfgang Denk
>
> I agree and disagree with the parenthetical part of your statement.
> Agree because it _wouldn't_ be a part of u-boot (technically it would be
> if someone put it in their default env for their specific board, but why
> would denx.de care?).
>
> Disagree because, while u-boot needs/uses some env variables,
> engineers/companies/end users are free to add variables and, I dare say,
> most do. If a given board needs to pass certain non u-boot parameters
> to linux, it would simply add that to its env (which already happens).
>
> I'm not sure you (Wolfgang and Kumar) are following my thought fully (or
> my ignorance is showing to everybody but me). The thought is to change
> the native format of the u-boot environment storage from the
> key-string/value-string pairs to the flat tree (OpenFirmware) format
> which still supports the same key-string/value-string capability (but
> can do more than that).
>
> The advantage, as I see it, is that it would be unifying and thus easier
> to maintain the common variables (call it the GRand Unifying Flat Tree
> (GRAFT) ;-). One language (flat tree), no shims, equivalent key/value
> utility (but a different underlying storage format), no visible
> difference for the users (but potentially an upgrade challenge for
> existing boards and env variables).
>
> The disadvantage is that it would be disruptive to u-boot and may cause
> some bloating and discomfort.
>
> gvb
> (the naive)
>
> P.S. For the non-USA readers: "may cause some bloating and discomfort"
> is a standard disclaimer on medicines advertised on TV over here.
>

Since I'm the guy responsible let me weigh in a bit.

For starters, yes it's possible to pass the whole env using the FT tree.
Use CONFIG_OF_HAS_UBOOT_ENV to pass the u-boot env to the FT tree.

As for the rest of the cat-fight, I'm afraid I don't have the energy
to jump in at the moment.

Perhaps tomorrow :)

Regards

Pantelis

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