[U-Boot-Users] Configuration System

Robert Schwebel robert at schwebel.de
Fri Apr 30 07:31:31 CEST 2004

Hi Jon, Hi Wolfgang, 

First of all, I would welcome such a project. 

On Fri, Apr 30, 2004 at 12:14:19AM +0200, Wolfgang Denk wrote:
> What exactly do you want  to  make  configurable?  And  how?  At  the
> moment,  configuration is done in a couple of places, like Makefiles,
> config.mk files included by Makefiles, {architecture,processor,board}
> dependend header and source files, and linker scripts.

Well, the idea of CFG vs. CONFIG variables does IMHO point into the
right direction. There are several things which could be changed by a
user (which needs to be a poweruser anyway, you cannot compare somebody
who works on bootloaders with occaional kernel compiling guys):

- baudrate
- bootdelay
- bootargs
- bootcmd
- cpu speed
- flash layout
- etc. 

> I think I have made myself clear what I think about this: i find  the
> ide  very  interesting,  but  I  can  see  no way how to implement it
> without making the code much harder to understand  and  to  maintain.

Hmm, what about this concept: first we leave everything as it is and add
the KConfig infrastructure. It can easily be done, I have done it in the
past and we can simply copy the stuff from PTXdist (which also uses
KConfig). The only thing that needs to be changed is the variable prefix
which is fixed to CONFIG_. Maybe UBOOT_. When this is done we could let
it generate another config.h file (invent a name here...) which will be
included by the BSPs which use the new mechanism. Everything will stay
as it is for the other boards and we can make some proof of concept
implementations for further review of the idea. 

> But I may be wrong. Please go on if you think you can provide patches
> that  show  how  this  can  be  done  for all existing architectures,
> processors and boards, without negative impact.

... which would not be necessary going that way. 

> One thing should be clear: there are certain things  that  require  a
> really  intimate  knowledge  of the innards of the processor, and the
> code. You must not expect that any configuration tool could enable an
> uninformed user to - for example - port U-Boot to new hardware.  THIS

Sure. But on the other hand there are several things which are more
"configuration" than "porting". These parts should be clearly separated. 

> I'd rather see that development happen in the public.

We can make a patch, post it on the list (I can offer my old
u-boot-config web page as a temporary home) and review it that way. 

 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
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