[U-Boot] [PATCH v2 09/22] omap4: add spl support for OMAP4 SDP

[Aneesh V]

Hi Wolfgang,

What's your final view on the Makefile structure of SPL.

best regards,
Aneesh

On Thursday 26 May 2011 06:55 PM, Aneesh V wrote:
> Hi Wolfgang,
>
> On Tuesday 17 May 2011 06:23 PM, Wolfgang Denk wrote:
>> Dear Aneesh V,
>>
>> In message<4DD26B36.4050102 at ti.com> you wrote:
>>>
>>> And how do you distinguish between the two cases at the top level
>>> Makefile? Using a CONFIG flag or on a per platform basis?
>>
>> The decision should not be make in the top level makefile, but in
>> spl/Makefile. And this can simply check if a board directory exists
>> in the first place.
>
> 1. How about the case where there is some board dependent code but also
> code shared by the boards(SoC based code). Will we have different
> 'Makefile's then - one for board and one for SoC. Will we then build
> different libraries at each leavel and link them together etc?
>
> 2. I think one key thing that you are perhaps missing is that in SPL
> the board level Makefile is not just meant for board level files.
> Instead it is used to pull together files from all the layers and make
> a custom image. IMHO, we will get into un-necessary complexities if we
> lose this property of SPL. We may rather spend efforts on making the
> regular U-Boot more configurable.
>
>>
>>> Why not just invoke the board level Makefile from the top-level
>>> Makefile and let it decide about the code-reuse by doing something like
>>> I did?
>>
>> Because then we need board specific directories and board specific
>> Makefiles even for those boards where no board specific code exists,
>> and all these Makefiles will be semi-identical copies of each other.
>>
>
> Considering point 2 above I think this is logical.
>
> The board level Makefile needs to have all the files. For the SoC level
> selection of files and the SoC level rules, include the respective *.mk
> files. Because in this case there are no board specific files there is
> nothing more in the Makefile. Please note that this may not be the case
> in general. Most boards, I suspect, may have some board specific files
> too.
>
> I wouldn't really consider the include statements as duplication of
> code. Instead, that was a way of avoiding duplication of code "given
> the constraints of the SPL model".
>
> best regards,
> Aneesh
>
>>>> Then we should adapt the directory and Makefile structure and allow
>>>> for such common code without need for separate spl/board/
>>>> directories.
>>>
>>> Do you have any specific proposals? I have a feeling that this may get
>>> un-necessarily complicated.
>>
>> Having to maintain multiple copies of identical Makefiles is more
>> complicated and error prone in the long run. Let's rather spoend a few
>> thoughts initially and solve this problem before it spreads.
>>
>> Best regards,
>>
>> Wolfgang Denk
>>