Heads up: Linus plans to kill ARM defconfigs

[Kyungmin Park]

On Fri, Jun 4, 2010 at 8:33 AM, Ryan Mallon <ryan at bluewatersys.com> wrote:
> Nicolas Pitre wrote:
>> On Fri, 4 Jun 2010, Ryan Mallon wrote:
>>
>>> Is it worth being a bit proactive and getting rid of some of them in
>>> advance? Things like spear3[012]0_defconfig are basically identically
>>> except for the board type. Combining all three of those would remove
>>> 1500 lines of code.
>>
>> Please go ahead with a patch.
>
> Hmm, not as easy as I thought. The three boards cannot be built into a
> single kernel since the arch/arm/mach-spear3xx/spear3[012]0.c files all
> extern a bunch of structs which have naming conflicts.
>
> It does look possible to rewrite that code so that all three boards can
> be built into a single kernel. I can try and put together a patch, but I
> don't have any hardware to test with.
>
> The at91 is actually in a similar state, where only one of the
> at91sam9260, at91sam9g45, etc can be selected. Again, it should be
> possible to rework the code so that most of the different cpus can be
> built into a single kernel. I'm sure other mach's are in a simliar
> state. Fixing these where possible would allow us to have single
> defconfigs per mach directory and reduce code churn, which is what Linus
> is really complaining about.
>
>>> Basically reduce down to one or two defconfigs for each mach directory
>>> which include as many boards and drivers as possible. People wanting
>>> more tailored configs can do that in their own trees.
>>
>> This actually should have been the plan from the start.  See for example
>> orion5x_defconfig which currently already supports 23 machines.

If target has several variants with different memory size, different
GPIOs. It's really hard to maintain and support.
To address this issues. we implement the detect routine and give
different system revision at bootloader side and kernel boot with this
information. with this approaches I can support 5 different targets
based on s5pc110.

In previous time, we usually make a kernel for each boards but it's
hard works and takes long time. So single kernel is best approaches
and it's possible at least similar CPUs. e.g. samsung s5p series.

As I know s5pc110 (aka s5pv210) and s5p644x is similar and can
possible to make single kernel.

Thank you,
Kyungmin Park