Re: kbuild question

[Kumar Gala <galak@kernel.crashing.org>]

On Feb 18, 2007, at 1:25 PM, Sam Ravnborg wrote:

>>>
>>> Sure, on powerpc for some of the embedded sub-architectures you  
>>> can only
>>> select a single board to build for.  For a lot of people this is  
>>> sufficient,
>>> however we are moving towards a world where you can easily build  
>>> in support
>>> for multiple boards into a single kernel.
>>>
>>> I'd like to have it such that if I'm only building support for  
>>> one board
>>> (CONFIG_ONLY_HAVE_ONE, not going to call it that, but for this  
>>> discussion its
>>> sufficient), you get a choice menu from Kconfig enforcing the  
>>> ability to only
>>> select one board.  However if !CONFIG_ONLY_HAVE_ONE than you can  
>>> select
>>> multiple boards to build into your kernel.
>>>
>>> if CONFIG_ONLY_HAVE_ONE is set we can optimize out the runtime  
>>> checks that get
>>> added for handling the multiple board case.
>>
>> On m68k we have the same problem, but what I'm what I'm  
>> considering is to
>> add a new mode for choice groups - at least one must be selected and
>> kconfig generates the extra information if only one is selected.
>
> How about extendign the current 'option' syntax to do this?
> So we could do something like:
>
> choice
> 	prompt "choice prompt"
> 	default VAL_FIRST
> 	option multivalue if !CONFIG_ONLY_HAVE_ONE
>
> config VAL_FIRST
> 	bool "first"
>
> config VAL_SECOND
> 	bool "second"
>
> endchoice
>
> It seems to fit well with how option is used today, and extends  
> current
> syntax nicely.

This works for me, however I dont have the first clue about hacking  
on kconfig code.

I'm happy to test out a patch if one of you guys wouldn't mind  
working something up.. or point me and what I should look at to do this.

- k