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

quoted

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>
---
 drivers/firmware/Kconfig                |  4 +-
 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 +
 drivers/net/wireless/ath/ath10k/Kconfig |  2 +-
 drivers/pinctrl/qcom/Kconfig            |  3 +-
 drivers/pinctrl/sunxi/Kconfig           |  6 +--
 include/linux/arm-smccc.h               | 10 ++++
 include/linux/qcom_scm.h                | 71 -------------------------
 11 files changed, 23 insertions(+), 84 deletions(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 220a58cf0a44..f7dd82ef0b9c 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig

@@ -203,9 +203,7 @@ config INTEL_STRATIX10_RSU
 	  Say Y here if you want Intel RSU support.
 
 config QCOM_SCM
-	tristate "Qcom SCM driver"
-	depends on ARM || ARM64
-	depends on HAVE_ARM_SMCCC
+	tristate
 	select RESET_CONTROLLER
 
 config QCOM_SCM_DOWNLOAD_MODE_DEFAULT

diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
index e9c6af78b1d7..3ddf739a6f9b 100644
--- a/drivers/gpu/drm/msm/Kconfig
+++ b/drivers/gpu/drm/msm/Kconfig

@@ -17,7 +17,7 @@ config DRM_MSM
 	select DRM_SCHED
 	select SHMEM
 	select TMPFS
-	select QCOM_SCM if ARCH_QCOM
+	select QCOM_SCM
 	select WANT_DEV_COREDUMP
 	select SND_SOC_HDMI_CODEC if SND_SOC
 	select SYNC_FILE

@@ -55,7 +55,7 @@ config DRM_MSM_GPU_SUDO
 
 config DRM_MSM_HDMI_HDCP
 	bool "Enable HDMI HDCP support in MSM DRM driver"
-	depends on DRM_MSM && QCOM_SCM
+	depends on DRM_MSM
 	default y
 	help
 	  Choose this option to enable HDCP state machine

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 124c41adeca1..989c83acbfee 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig

@@ -308,7 +308,7 @@ config APPLE_DART
 config ARM_SMMU
 	tristate "ARM Ltd. System MMU (SMMU) Support"
 	depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
-	depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y
+	select QCOM_SCM
 	select IOMMU_API
 	select IOMMU_IO_PGTABLE_LPAE
 	select ARM_DMA_USE_IOMMU if ARM