Re: [PATCH 2/2] [v2] qcom_scm: hide Kconfig symbol

From: Alex Elder
Date: Tue Sep 28 2021 - 09:29:56 EST

On 9/28/21 2:50 AM, Arnd Bergmann wrote:
From: Arnd Bergmann <arnd@xxxxxxxx>

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

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

- 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, drop the 'select RESET_CONTROLLER' statement.
According to my testing this still builds fine, and the QCOM
platform selects this symbol already.

Acked-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Changes in v2:
- drop the 'select RESET_CONTROLLER' line, rather than adding
more of the same
drivers/firmware/Kconfig | 5 +-
drivers/gpu/drm/msm/Kconfig | 4 +-
drivers/iommu/Kconfig | 2 +-
drivers/media/platform/Kconfig | 2 +-
drivers/mmc/host/Kconfig | 2 +-
drivers/net/ipa/Kconfig | 1 +

For drivers/net/ipa/Kconfig, looks good to me.
Nice simplification.

Acked-by: Alex Elder <elder@xxxxxxxxxx>

drivers/net/wireless/ath/ath10k/Kconfig | 2 +-
drivers/pinctrl/qcom/Kconfig | 3 +-
include/linux/arm-smccc.h | 10 ++++
include/linux/qcom_scm.h | 71 -------------------------
10 files changed, 20 insertions(+), 82 deletions(-)

. . .