[U-Boot] [RFC PATCH v1 0/1] Migrate IMAGE_FORMAT_LEGACY to Kconfig

[Alex Kiernan]

On Thu, Apr 19, 2018 at 8:39 PM, Tom Rini <trini at konsulko.com> wrote:
> On Thu, Apr 19, 2018 at 04:52:30AM +0000, Alex Kiernan wrote:
>>
>> On the face of it, this is a straightforward moveconfig, but because
>> of how CONFIG_FIT_SIGNATURE, CONFIG_IMAGE_FORMAT_LEGACY and
>> CONFIG_DISABLE_IMAGE_LEGACY interacted when you enabled
>> CONFIG_FIT_SIGNATURE, you got CONFIG_IMAGE_FORMAT_LEGACY disabled
>> immediately unless you had some way of explicitly enabling it
>> elsewhere.
>>
>> Kconfig doesn't give us this - CONFIG_IMAGE_FORMAT_LEGACY starts off
>> enabled, CONFIG_FIT_SIGNATURE starts off disabled and if you enable
>> CONFIG_FIT_SIGNATURE then CONFIG_IMAGE_FORMAT_LEGACY stays enabled.
>>
>> Is there some way to preserve the existing behaviour through Kconfig
>> that I've failed to figure out?
>
> When I do these, it's a multi-step moveconfig.py that goes something
> like:
> - Introduce FOO (no deps)
> - moveconfig.py -y it.
> - Introduce BAR (no deps)
> - moveconfig.py -y it.
> - for FILE in configs/*defconfig;do grep -q FOO $FILE || echo '#
>   CONFIG_FOO is not set' >> $FILE;done
> - Repeat the for loop but for BAR.
> - Introduce deps
> - moveconfig.py -sC
> - Build before/after for a few boards that I know are tricky, use
>   buildman -SCvel/Ssdel to confirm size changes didn't happen.
> - If good, world-build checking sizes.
>
> And in some cases like this particular one, there might need to be an
> initial first comment to invert the logic, and as that can be tricky
> when adding a new option that _should_ be default y, first I add it
> without default y, moveconfig.py -y it, for loop like above, then add
> default y and moveconfig.py -s.
>

Thanks, let me give that a go...

There's a second concern I have once the pieces are all in there when
you're making changes through menuconfig (and friends)... there's no
"weak" default enable in Kconfig (at least as far as I can tell) so if
you select FIT_SIGNATURE, you have to explicitly go and de-select
IMAGE_FORMAT_LEGACY.

Am I missing something, or can we live with that?

-- 
Alex Kiernan