[U-Boot] Removing the need for boards.cfg

[Simon Glass]

Hi Tom,

On 8 August 2014 05:59, Tom Rini <trini at ti.com> wrote:
> On Fri, Aug 08, 2014 at 05:06:03AM -0600, Simon Glass wrote:
>> Hi Masahiro,
>>
>> On 1 August 2014 06:22, Masahiro Yamada <yamada.m at jp.panasonic.com> wrote:
>> > Hi.
>> >
>> >
>> >
>> > On Fri, 1 Aug 2014 12:48:44 +0100
>> > Simon Glass <sjg at chromium.org> wrote:
>> >
>> >> Hi,
>> >>
>> >> At present, as a work-around, we generate boards.cfg if needed. This
>> >> is quite a slow process since each board config must be fully
>> >> processed.
>> >>
>> >> What can we do to improve this? We only need a small number of options
>> >> in order to start buildman - things like CONFIG_SYS_ARCH,
>> >> CONFIG_SYS_CPU, etc.
>> >>
>> >> I wonder if we could run a script which adds these to the defconfigs
>> >> for each board and then apply a patch to mainline? Would that require
>> >> removing the options from the config.h files? Or could we do that
>> >> later as a separate step?
>> >>
>> >
>> >
>> > We cannot add CONFIG_SYS_ARCH, CONFIG_SYS_CPU, etc. to defconfigs
>> > because they are not user-editable options.
>> > (They must be always selected in correct combination.)
>> >
>> > This is already discussed when I posted the RFC version of the Kconfig series.
>>
>> My understanding is that if you have a 'select' option in Kconfig then
>> it will be selected always, but it will still appear in the defconfig.
>> I think that is the way the kernel works. So there are options that
>> cannot be changed, and don't appear in the menu, but they are selected
>> just the same.
>
> Maybe we came up with the wrong answer during RFC on Kconfig then.  It's
> good if selecting say CONFIG_TARGET_AM335X_EVM results in
> CONFIG_SYS_ARCH="arm", CONFIG_SYS_CPU="armv7", etc.
>
> I _think_ the problem here is what I ran into with doing CONS_INDEX
> patches.  You cannot do 'select SYS_CPU="armv7"'.  So we would instead
> need to get rid of CONFIG_SYS_CPU and instead do CONFIG_SYS_CPU_ARMV7,
> etc, etc.

Well I think we should run this one to ground first - if a 'select'
item doesn't appear in Kconfig then I think we have a bit of a
problem. Will await Masahiro's thoughts.

Regards,
Simon