[U-Boot] RFQ: Makefile cleanup

[Wolfgang Denk]

Dear Graeme Russ,

In message <AANLkTin-b-yyRaWhUBYLosoDO7RvuK7Hs=FttRBYxoxk at mail.gmail.com> you wrote:
>
> I feel that boards.cfg defines configurations, and therfore each
> additional field is, by definition, a configuration option and should be
> prefixed with CONFIG_

Good point, thanks.

> I actually got really confused with TEXT_BASE and thought it was some kind
> of standard environment variable that ld magically used - it wasn't until
> I spent a day trolling through the makfile et al that I finally figurfed
> out that the linker script was 'made' and TEXT_BASE was just another
> define and I could add more to the parsing of the ld script. Having it as
> CONFIG_TEXT_BASE or CONFIG_SYS_TEXT_BASE would have alerted me straight up

Yes, I agree. Renaming TEXT_BASE into CONFIG_SYS_TEXT_BASE is probably
the best solution here.

> A couple of other questions:
>  - How do you un-define a CONFIG option via boards.cfg?

We don't. We cannot. The auto-generated config.h is included before
the board config iule (which is necessary so the config options in the
former can influence processing of the latter), but that means that
any #undef in config.h will simply be overridden by a following
#define in the board config file.

We don't need #undef so far, and we should try never to need it. Use
additive logic instead, #define'ing only what you really (and always)
need, and add configurable options (and this only when really needed).

>  - What happens when you try to re-define an option already in the board
>    configuration file?

You get an error. For the same reasons. Don't do that.

> Each board could have a main config with all the common configuration
> values and a number of secondary includes (which include the primary) for
> each specific configuration. The entry in boards.cfg would select a
> specific config_xxx.h file

That would be an option as well, but it would add a lot of tiny files,
and not bring us any closer to a Kconfig based system.

Best regards,

Wolfgang Denk

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