[meta-freescale] u-boot fails building with gk802 (hdmi dongle) as MACHINE, hard-float issue?

[Christian Betz]

i'm starting to figure out what is going on.

the short story, I think, is that all the other boards are using soft
float and it works fine because they are using a separate and newer
branch of uboot that fixed a build-system related bug [1].

in other words: it's totally fine (desirable, actually) to build
u-boot with -msoft-float and then boot a kernel and userspace with
hard float. i think the issue I was running into with the imx6 dongle
uboot has to do with something being erroneously pulled in from the
hosts libgcc (which was compiled with hard float support) [1]. the
build fails because it refuses to mix the soft-float u-boot binaries
with the the hard-float stuff erroneously pulled from libgcc.

i still don't know what the exact fix is because nobody mentions a
particular commit but i am on the trail. i've done a little digging
already but didn't get very far (USE_PRIVATE_LIBGCC doesn't appear to
be used anywhere in any recipes so that couldn't be the fix).

part of me wonders how hard it would be to port the board from the
older uboot-imx6dongle to the official uboot-imx because this would
probably solve the problem. more details to follow, i hope.

--christian

1. http://u-boot.10912.n7.nabble.com/U-Boot-RFC-PATCH-ARMV7-Patch-to-fix-hard-float-build-issues-td22107.html

On Fri, Aug 30, 2013 at 3:23 AM, Christian Betz
<christian.betz at gmail.com> wrote:
> On Thu, Aug 29, 2013 at 4:14 PM, Otavio Salvador
> <otavio at ossystems.com.br> wrote:
>> On Tue, Aug 27, 2013 at 10:25 PM, Christian Betz
>> <christian.betz at gmail.com> wrote:
>>> I found the answer and I was able to build u-boot (and
>>> core-image-base) successfully after modifying
>>> arch/arm/cpu/armv7/config.mk as described at the link below [1]
>>
>> This is probably something which has been fixed with a specific patch
>> in mainline so the better way would be to 'export' the patch and use
>> it here.
>>
>> Can you try git blame and check it?
>
> I tried, but I'm having a really hard time figuring out how the fpu
> selection works for other boards or finding any code related to
> hard-float that I can blame. since config.mk has the -msoft-float in
> u-boot master and there no patches I can find that would change it.
>
> in other words, mainline u-boot appears to still have the following
> line in arch/arm/cpu/armv7/config.mk:
>
>  PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
>
> and I can't find any recipes/patches that are changing it. so i'm
> scratching my head wondering how the heck u-boot builds with hard
> float for all the other boards.
>
> I'm hoping someone else has some pointers. I would like to do this the
> "right" way but i'm currently lost. Or maybe i've just been awake too
> long ;)
>
> --christian
>
>
>
>>
>> --
>> Otavio Salvador                             O.S. Systems
>> http://www.ossystems.com.br        http://code.ossystems.com.br
>> Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750
>
>
>
> --
> "the new garbage collector will be an arena-based, quad-color
> incremental, generational, non-copying, high-speed, cache-optimized
> garbage collector" -- LuaJIT Roadmap



-- 
"the new garbage collector will be an arena-based, quad-color
incremental, generational, non-copying, high-speed, cache-optimized
garbage collector" -- LuaJIT Roadmap