[U-Boot] [PATCH v3 6/7] kconfig: remove unneeded dependency on !SPL_BUILD

[Masahiro Yamada]

Hi Simon, Stephen,



On Mon, 23 Feb 2015 10:44:54 -0700
Simon Glass <sjg at chromium.org> wrote:

> Hi Stephen,
> 
> On 23 February 2015 at 10:33, Stephen Warren <swarren at wwwdotorg.org> wrote:
> > On 02/23/2015 07:02 AM, Simon Glass wrote:
> >>
> >> Hi Masahiro,
> >>
> >> On 20 February 2015 at 19:37, Masahiro YAMADA <yamada.m at jp.panasonic.com>
> >> wrote:
> >>>
> >>> Hi Simon,
> >>>
> >>>
> >>> 2015-02-21 11:28 GMT+09:00 Simon Glass <sjg at chromium.org>:
> >>>>
> >>>> Hi Masahiro,
> >>>>
> >>>> On 20 February 2015 at 17:54, Masahiro YAMADA
> >>>> <yamada.m at jp.panasonic.com> wrote:
> >>>>>
> >>>>> Hi Simon, Stephen,
> >>>>>
> >>>>>
> >>>>> 2015-02-21 3:39 GMT+09:00 Simon Glass <sjg at chromium.org>:
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> On 20 February 2015 at 10:54, Stephen Warren <swarren at wwwdotorg.org>
> >>>>>> wrote:
> >>>>>>>
> >>>>>>> On 02/20/2015 10:06 AM, Simon Glass wrote:
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> +Stephen
> >>>>>>>>
> >>>>>>>> Hi Masahiro,
> >>>>>>>>
> >>>>>>>> On 19 February 2015 at 22:25, Masahiro Yamada
> >>>>>>>> <yamada.m at jp.panasonic.com>
> >>>>>>>> wrote:
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Now CONFIG_SPL_BUILD is not defined in Kconfig, so
> >>>>>>>>> "!depends on SPL_BUILD" and "if !SPL_BUILD" are redundant.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> >>>>>>>>> index 41f3220..700e2a8 100644
> >>>>>>>>> --- a/arch/arm/Kconfig
> >>>>>>>>> +++ b/arch/arm/Kconfig
> >>>>>>>>> @@ -739,9 +739,8 @@ config TEGRA
> >>>>>>>>>           bool "NVIDIA Tegra"
> >>>>>>>>>           select SUPPORT_SPL
> >>>>>>>>>           select SPL
> >>>>>>>>> -       select OF_CONTROL if !SPL_BUILD
> >>>>>>>>> -       select CPU_ARM720T if SPL_BUILD
> >>>>>>>>> -       select CPU_V7 if !SPL_BUILD
> >>>>>>>>> +       select OF_CONTROL
> >>>>>>>>> +       select CPU_V7
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> Sorry if I have missed something here. On Tegra most unfortunately
> >>>>>>>> the
> >>>>>>>> SPL uses ARMv4t and U-Boot proper uses ARMv7. In fact that is the
> >>>>>>>> only
> >>>>>>>> reason that Tegra has SPL. Doesn't this change with this commit?
> >>>>>
> >>>>>
> >>>>>
> >>>>> No.   I think behavior is still the same as before.
> >>>>>
> >>>>> In a single .config, we cannot define two CPUs in Kconfig.
> >>>>>
> >>>>> So, we only define CPU_V7, for the main processors.
> >>>>>
> >>>>> For SPL, we override the "CPU" in config.mk
> >>>>>
> >>>>> ifdef CONFIG_SPL_BUILD
> >>>>> ifdef CONFIG_TEGRA
> >>>>> CPU := arm720t
> >>>>> endif
> >>>>> endif
> >>>>>
> >>>>> I know what you might be saying is, this is too ugly. Yes.
> >>>>>
> >>>>> I think we can do a little better with further rafactoring,
> >>>>> but the basic idea is, SPL of Tegra is a special case.
> >>>>>
> >>>>
> >>>> Yes I saw that, I understand now. So SPL_BUILD is no longer available
> >>>> in Kconfig, but is still available in Makefiles, right?
> >>>
> >>>
> >>> Yes, exactly!
> >>
> >>
> >> This all works fine on Tegra for me. However I like to suggest
> >> dropping a few patches in this series.
> >>
> >> I don't think it is worth using ARCH_MALLOC_F_LEN. In fact for me the
> >> Tegra defconfig looks OK and SPL is built correctly.
> >>
> >> My remaining question is about that Tegra seems to want
> >> USE_PRIVATE_LIBGCC for SPL but not for U-Boot. I'm not sure why, nor
> >> whether it matters. It seems to work find using it for both.
> >
> >
> > Depending on the toolchain, we actively need USE_PRIVATE_LIBGCC for SPL, and
> > don't /need/ it for non-SPL. However, enabling USE_PRIVATE_LIBGCC for
> > non-SPL likely won't hurt.
> >
> > The issue is that the libgcc bundled with most compilers is for ARMv7 (since
> > we tend to use ARMv7 compilers, since the main U-boot is built for ARMv7).
> > That bundled libgcc won't work on the ARMv4 that runs the SPL, so we need
> > USE_PRIVATE_LIBGCC there. The private libgcc bundled with U-Boot should work
> > fine when built for either CPU, so it is OK to always use it, rather than
> > only use it when strictly needed.
> 
> Ah yes, I think I knew that once. So in short Masahiro's patch here
> should be fine.
> 


Yes, Stephen explained all about my intention.

I think CONFIG_USE_PRIVATE_LIBGCC is also necessary for Raspberry Pi 1 for example.



Moreover, I had already posted this patch:
http://patchwork.ozlabs.org/patch/438360/

I'd like to expand the private library to all the ARM boards.


Linux Kernel includes the library in its source tree.

I think it is generally a good idea to reduce the depencendy on particular toolchains.
Agree?

Best Regards
Masahiro Yamada