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

[Stephen Warren]

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.