Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

Arnd Bergmann [off-list ref] writes:

From: Arnd Bergmann <arnd@arndb.de>

Now that SCM can be a loadable module, we have to add another
dependency to avoid link failures when ipa or adreno-gpu are
built-in:

aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'

ld.lld: error: undefined symbol: qcom_scm_is_available

quoted

quoted

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referenced by adreno_gpu.c
              gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load)
in archive drivers/built-in.a

This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
use a similar dependency here to what we have for QCOM_RPROC_COMMON,
but that causes dependency loops from other things selecting QCOM_SCM.

This appears to be an endless problem, so try something different this
time:

 - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
   but that is simply selected by all of its users

 - All the stubs in include/linux/qcom_scm.h can go away

 - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
   allow compile-testing QCOM_SCM on all architectures.

 - To avoid a circular dependency chain involving RESET_CONTROLLER
   and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
   the latter one to 'select'.

The last bit is rather annoying, as drivers should generally never
'select' another subsystem, and about half the users of the reset
controller interface do this anyway.

Nevertheless, this version seems to pass all my randconfig tests
and is more robust than any of the prior versions.

Comments?

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

[...]

I assume I can continue to build test ATH10K_SNOC with x86 as before?
That's important for me. If yes, then:

Acked-by: Kalle Valo <redacted>

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

On Tue, Sep 28, 2021 at 9:05 AM Kalle Valo [off-list ref] wrote:

Arnd Bergmann [off-list ref] writes:

quoted

From: Arnd Bergmann <arnd@arndb.de>

I assume I can continue to build test ATH10K_SNOC with x86 as before?
That's important for me. If yes, then:

Acked-by: Kalle Valo <redacted>

--
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Yes, the difference is that this will then also build the qcom_scm module, but
that should not cause any problems after the other changes in this patch.

      Arnd