[U-Boot] want to clarify a couple things about vendor common/ directories

[Wolfgang Denk]

Dear Robert,

In message <alpine.LFD.2.20.1604130835360.4548 at localhost.localdomain> you wrote:
> 
>   (in fact, i can see that of the several vendors that have common/
> directories, only ti/common/ has a Kconfig file, so i'm concluding
> that a common/ directory containing a Kconfig file is more the
> exception rather than the norm. ti/common/ seems like a special case,
> in that it contains just some board_detect code, and its Kconfig would
> be explicitly sourced by the subset of ti boards for which it's
> relevant, so that makes sense. but, as i mentioned, that's the only
> example i see.)

Kconfig stuff is still relatively new, and not many vendors update
their code on a regular base, unless pressed into it ...

> i suppose it might have been possible for the build process to add the
> common directory to the include search path for header files, but it's

I think we tried this (many, many years ago), and it caused all kinds
of problems; the vendor specific code is often... umm... vendor
specific.

> clear that wasn't done so common header file inclusion *needs* that
> "../common/whatever.h" form, correct?

As is, yes.

>   finally, in terms of pulling in common source files, i'm just going
> to be appalled by the occasional form of this:
> 
>   amcc/bubinga/flash.c:#include "../common/flash.c"
>   amcc/walnut/flash.c:#include "../common/flash.c"
>   amcc/bamboo/flash.c:#include "../common/flash.c"
>   amcc/luan/flash.c:#include "../common/flash.c"

I share your dislike...

> or is textual inclusion of source files from a common directory
> acceptable practice? i normally really dislike this, but is doing that
> in this specific context in u-boot considered acceptable?

This is very, very old code. It would not be accepted these days.
And if you look closer, the code is totally redundant, as the standard
CFI driver would probably work on most of these boards - if not
everywhere.

I would not be surprised to see these boards on the remove list in a
not too far future...

>   in any event, the regular way appears to be having a Makefile
> controlling what vendor-common code gets compiled, and Kconfig files
> elsewhere allowing the selection of config options to drive that
> process, is that about right?
> 
>   am i missing anything regarding proper common/ vendor usage?

Kconfig usage is expected to grow...


Best regards,

Wolfgang Denk

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