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

From: Kalle Valo <[email-masked]>
Date: Tue, 28 Sep 2021 10:03:25 +0300

Arnd Bergmann <[email-masked]> writes:

> From: Arnd Bergmann <[email-masked]>
>
> 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
>>>> 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 <[email-masked]>

[...]

> diff --git a/drivers/net/wireless/ath/ath10k/Kconfig b/drivers/net/wireless/ath/ath10k/Kconfig
> index 741289e385d5..ca007b800f75 100644
> --- a/drivers/net/wireless/ath/ath10k/Kconfig
> +++ b/drivers/net/wireless/ath/ath10k/Kconfig
> @@ -44,7 +44,7 @@ config ATH10K_SNOC
>  	tristate "Qualcomm ath10k SNOC support"
>  	depends on ATH10K
>  	depends on ARCH_QCOM || COMPILE_TEST
> -	depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
> +	select QCOM_SCM
>  	select QCOM_QMI_HELPERS
>  	help
>  	  This module adds support for integrated WCN3990 chip connected

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 <[email-masked]>

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