[PATCH] [RFC] qcom_scm: hide Kconfig symbol

[PATCH] [RFC] qcom_scm: hide Kconfig symbol

[Arnd Bergmann]

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
>>> 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
diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 157c924686e4..80321e03809a 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -565,7 +565,7 @@ config VIDEO_QCOM_VENUS
 	depends on VIDEO_DEV && VIDEO_V4L2 && QCOM_SMEM
 	depends on (ARCH_QCOM && IOMMU_DMA) || COMPILE_TEST
 	select QCOM_MDT_LOADER if ARCH_QCOM
-	select QCOM_SCM if ARCH_QCOM
+	select QCOM_SCM
 	select VIDEOBUF2_DMA_CONTIG
 	select V4L2_MEM2MEM_DEV
 	help
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 71313961cc54..95b3511b0560 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -547,7 +547,7 @@ config MMC_SDHCI_MSM
 	depends on MMC_SDHCI_PLTFM
 	select MMC_SDHCI_IO_ACCESSORS
 	select MMC_CQHCI
-	select QCOM_SCM if MMC_CRYPTO && ARCH_QCOM
+	select QCOM_SCM if MMC_CRYPTO
 	help
 	  This selects the Secure Digital Host Controller Interface (SDHCI)
 	  support present in Qualcomm SOCs. The controller supports
diff --git a/drivers/net/ipa/Kconfig b/drivers/net/ipa/Kconfig
index 8f99cfa14680..d037682fb7ad 100644
--- a/drivers/net/ipa/Kconfig
+++ b/drivers/net/ipa/Kconfig
@@ -4,6 +4,7 @@ config QCOM_IPA
 	depends on ARCH_QCOM || COMPILE_TEST
 	depends on QCOM_RPROC_COMMON || (QCOM_RPROC_COMMON=n && COMPILE_TEST)
 	select QCOM_MDT_LOADER if ARCH_QCOM
+	select QCOM_SCM
 	select QCOM_QMI_HELPERS
 	help
 	  Choose Y or M here to include support for the Qualcomm
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
diff --git a/drivers/pinctrl/qcom/Kconfig b/drivers/pinctrl/qcom/Kconfig
index 32ea2a8ec02b..5ff4207df66e 100644
--- a/drivers/pinctrl/qcom/Kconfig
+++ b/drivers/pinctrl/qcom/Kconfig
@@ -3,7 +3,8 @@ if (ARCH_QCOM || COMPILE_TEST)
 
 config PINCTRL_MSM
 	tristate "Qualcomm core pin controller driver"
-	depends on GPIOLIB && (QCOM_SCM || !QCOM_SCM) #if QCOM_SCM=m this can't be =y
+	depends on GPIOLIB
+	select QCOM_SCM
 	select PINMUX
 	select PINCONF
 	select GENERIC_PINCONF
diff --git a/drivers/pinctrl/sunxi/Kconfig b/drivers/pinctrl/sunxi/Kconfig
index 33751a6a0757..3447d2744ca3 100644
--- a/drivers/pinctrl/sunxi/Kconfig
+++ b/drivers/pinctrl/sunxi/Kconfig
@@ -29,7 +29,7 @@ config PINCTRL_SUN6I_A31
 config PINCTRL_SUN6I_A31_R
 	bool "Support for the Allwinner A31 R-PIO"
 	default MACH_SUN6I
-	depends on RESET_CONTROLLER
+	select RESET_CONTROLLER
 	select PINCTRL_SUNXI
 
 config PINCTRL_SUN8I_A23
@@ -55,7 +55,7 @@ config PINCTRL_SUN8I_A83T_R
 config PINCTRL_SUN8I_A23_R
 	bool "Support for the Allwinner A23 and A33 R-PIO"
 	default MACH_SUN8I
-	depends on RESET_CONTROLLER
+	select RESET_CONTROLLER
 	select PINCTRL_SUNXI
 
 config PINCTRL_SUN8I_H3
@@ -81,7 +81,7 @@ config PINCTRL_SUN9I_A80
 config PINCTRL_SUN9I_A80_R
 	bool "Support for the Allwinner A80 R-PIO"
 	default MACH_SUN9I
-	depends on RESET_CONTROLLER
+	select RESET_CONTROLLER
 	select PINCTRL_SUNXI
 
 config PINCTRL_SUN50I_A64
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 7d1cabe15262..63ccb5252190 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -321,10 +321,20 @@ asmlinkage unsigned long __arm_smccc_sve_check(unsigned long x0);
  * from register 0 to 3 on return from the SMC instruction.  An optional
  * quirk structure provides vendor specific behavior.
  */
+#ifdef CONFIG_HAVE_ARM_SMCCC
 asmlinkage void __arm_smccc_smc(unsigned long a0, unsigned long a1,
 			unsigned long a2, unsigned long a3, unsigned long a4,
 			unsigned long a5, unsigned long a6, unsigned long a7,
 			struct arm_smccc_res *res, struct arm_smccc_quirk *quirk);
+#else
+static inline void __arm_smccc_smc(unsigned long a0, unsigned long a1,
+			unsigned long a2, unsigned long a3, unsigned long a4,
+			unsigned long a5, unsigned long a6, unsigned long a7,
+			struct arm_smccc_res *res, struct arm_smccc_quirk *quirk)
+{
+	*res = (struct arm_smccc_res){};
+}
+#endif
 
 /**
  * __arm_smccc_hvc() - make HVC calls
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index c0475d1c9885..81cad9e1e412 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -61,7 +61,6 @@ enum qcom_scm_ice_cipher {
 #define QCOM_SCM_PERM_RW (QCOM_SCM_PERM_READ | QCOM_SCM_PERM_WRITE)
 #define QCOM_SCM_PERM_RWX (QCOM_SCM_PERM_RW | QCOM_SCM_PERM_EXEC)
 
-#if IS_ENABLED(CONFIG_QCOM_SCM)
 extern bool qcom_scm_is_available(void);
 
 extern int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus);
@@ -115,74 +114,4 @@ extern int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
 extern int qcom_scm_lmh_profile_change(u32 profile_id);
 extern bool qcom_scm_lmh_dcvsh_available(void);
 
-#else
-
-#include <linux/errno.h>
-
-static inline bool qcom_scm_is_available(void) { return false; }
-
-static inline int qcom_scm_set_cold_boot_addr(void *entry,
-		const cpumask_t *cpus) { return -ENODEV; }
-static inline int qcom_scm_set_warm_boot_addr(void *entry,
-		const cpumask_t *cpus) { return -ENODEV; }
-static inline void qcom_scm_cpu_power_down(u32 flags) {}
-static inline u32 qcom_scm_set_remote_state(u32 state,u32 id)
-		{ return -ENODEV; }
-
-static inline int qcom_scm_pas_init_image(u32 peripheral, const void *metadata,
-		size_t size) { return -ENODEV; }
-static inline int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr,
-		phys_addr_t size) { return -ENODEV; }
-static inline int qcom_scm_pas_auth_and_reset(u32 peripheral)
-		{ return -ENODEV; }
-static inline int qcom_scm_pas_shutdown(u32 peripheral) { return -ENODEV; }
-static inline bool qcom_scm_pas_supported(u32 peripheral) { return false; }
-
-static inline int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val)
-		{ return -ENODEV; }
-static inline int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
-		{ return -ENODEV; }
-
-static inline bool qcom_scm_restore_sec_cfg_available(void) { return false; }
-static inline int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare)
-		{ return -ENODEV; }
-static inline int qcom_scm_iommu_secure_ptbl_size(u32 spare, size_t *size)
-		{ return -ENODEV; }
-static inline int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare)
-		{ return -ENODEV; }
-extern inline int qcom_scm_mem_protect_video_var(u32 cp_start, u32 cp_size,
-						 u32 cp_nonpixel_start,
-						 u32 cp_nonpixel_size)
-		{ return -ENODEV; }
-static inline int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
-		unsigned int *src, const struct qcom_scm_vmperm *newvm,
-		unsigned int dest_cnt) { return -ENODEV; }
-
-static inline bool qcom_scm_ocmem_lock_available(void) { return false; }
-static inline int qcom_scm_ocmem_lock(enum qcom_scm_ocmem_client id, u32 offset,
-		u32 size, u32 mode) { return -ENODEV; }
-static inline int qcom_scm_ocmem_unlock(enum qcom_scm_ocmem_client id,
-		u32 offset, u32 size) { return -ENODEV; }
-
-static inline bool qcom_scm_ice_available(void) { return false; }
-static inline int qcom_scm_ice_invalidate_key(u32 index) { return -ENODEV; }
-static inline int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
-				       enum qcom_scm_ice_cipher cipher,
-				       u32 data_unit_size) { return -ENODEV; }
-
-static inline bool qcom_scm_hdcp_available(void) { return false; }
-static inline int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt,
-		u32 *resp) { return -ENODEV; }
-
-static inline int qcom_scm_qsmmu500_wait_safe_toggle(bool en)
-		{ return -ENODEV; }
-
-static inline int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
-				     u64 limit_node, u32 node_id, u64 version)
-		{ return -ENODEV; }
-
-static inline int qcom_scm_lmh_profile_change(u32 profile_id) { return -ENODEV; }
-
-static inline bool qcom_scm_lmh_dcvsh_available(void) { return -ENODEV; }
-#endif
 #endif
-- 
2.29.2

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

[Bjorn Andersson]

On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:

> 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
> >>> 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'.

Can you please help me understand why this is part of the same patch?

> 
> 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?
> 

I like it!

It's less confusing than the current scheme, so should be easier to
get right. And I like the fact that we don't need the stubs anymore.


@John, could you please have a look at this as well, wrt GKI.

Regards,
Bjorn

> 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
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 157c924686e4..80321e03809a 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -565,7 +565,7 @@ config VIDEO_QCOM_VENUS
>  	depends on VIDEO_DEV && VIDEO_V4L2 && QCOM_SMEM
>  	depends on (ARCH_QCOM && IOMMU_DMA) || COMPILE_TEST
>  	select QCOM_MDT_LOADER if ARCH_QCOM
> -	select QCOM_SCM if ARCH_QCOM
> +	select QCOM_SCM
>  	select VIDEOBUF2_DMA_CONTIG
>  	select V4L2_MEM2MEM_DEV
>  	help
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 71313961cc54..95b3511b0560 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -547,7 +547,7 @@ config MMC_SDHCI_MSM
>  	depends on MMC_SDHCI_PLTFM
>  	select MMC_SDHCI_IO_ACCESSORS
>  	select MMC_CQHCI
> -	select QCOM_SCM if MMC_CRYPTO && ARCH_QCOM
> +	select QCOM_SCM if MMC_CRYPTO
>  	help
>  	  This selects the Secure Digital Host Controller Interface (SDHCI)
>  	  support present in Qualcomm SOCs. The controller supports
> diff --git a/drivers/net/ipa/Kconfig b/drivers/net/ipa/Kconfig
> index 8f99cfa14680..d037682fb7ad 100644
> --- a/drivers/net/ipa/Kconfig
> +++ b/drivers/net/ipa/Kconfig
> @@ -4,6 +4,7 @@ config QCOM_IPA
>  	depends on ARCH_QCOM || COMPILE_TEST
>  	depends on QCOM_RPROC_COMMON || (QCOM_RPROC_COMMON=n && COMPILE_TEST)
>  	select QCOM_MDT_LOADER if ARCH_QCOM
> +	select QCOM_SCM
>  	select QCOM_QMI_HELPERS
>  	help
>  	  Choose Y or M here to include support for the Qualcomm
> 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
> diff --git a/drivers/pinctrl/qcom/Kconfig b/drivers/pinctrl/qcom/Kconfig
> index 32ea2a8ec02b..5ff4207df66e 100644
> --- a/drivers/pinctrl/qcom/Kconfig
> +++ b/drivers/pinctrl/qcom/Kconfig
> @@ -3,7 +3,8 @@ if (ARCH_QCOM || COMPILE_TEST)
>  
>  config PINCTRL_MSM
>  	tristate "Qualcomm core pin controller driver"
> -	depends on GPIOLIB && (QCOM_SCM || !QCOM_SCM) #if QCOM_SCM=m this can't be =y
> +	depends on GPIOLIB
> +	select QCOM_SCM
>  	select PINMUX
>  	select PINCONF
>  	select GENERIC_PINCONF
> diff --git a/drivers/pinctrl/sunxi/Kconfig b/drivers/pinctrl/sunxi/Kconfig
> index 33751a6a0757..3447d2744ca3 100644
> --- a/drivers/pinctrl/sunxi/Kconfig
> +++ b/drivers/pinctrl/sunxi/Kconfig
> @@ -29,7 +29,7 @@ config PINCTRL_SUN6I_A31
>  config PINCTRL_SUN6I_A31_R
>  	bool "Support for the Allwinner A31 R-PIO"
>  	default MACH_SUN6I
> -	depends on RESET_CONTROLLER
> +	select RESET_CONTROLLER
>  	select PINCTRL_SUNXI
>  
>  config PINCTRL_SUN8I_A23
> @@ -55,7 +55,7 @@ config PINCTRL_SUN8I_A83T_R
>  config PINCTRL_SUN8I_A23_R
>  	bool "Support for the Allwinner A23 and A33 R-PIO"
>  	default MACH_SUN8I
> -	depends on RESET_CONTROLLER
> +	select RESET_CONTROLLER
>  	select PINCTRL_SUNXI
>  
>  config PINCTRL_SUN8I_H3
> @@ -81,7 +81,7 @@ config PINCTRL_SUN9I_A80
>  config PINCTRL_SUN9I_A80_R
>  	bool "Support for the Allwinner A80 R-PIO"
>  	default MACH_SUN9I
> -	depends on RESET_CONTROLLER
> +	select RESET_CONTROLLER
>  	select PINCTRL_SUNXI
>  
>  config PINCTRL_SUN50I_A64
> diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> index 7d1cabe15262..63ccb5252190 100644
> --- a/include/linux/arm-smccc.h
> +++ b/include/linux/arm-smccc.h
> @@ -321,10 +321,20 @@ asmlinkage unsigned long __arm_smccc_sve_check(unsigned long x0);
>   * from register 0 to 3 on return from the SMC instruction.  An optional
>   * quirk structure provides vendor specific behavior.
>   */
> +#ifdef CONFIG_HAVE_ARM_SMCCC
>  asmlinkage void __arm_smccc_smc(unsigned long a0, unsigned long a1,
>  			unsigned long a2, unsigned long a3, unsigned long a4,
>  			unsigned long a5, unsigned long a6, unsigned long a7,
>  			struct arm_smccc_res *res, struct arm_smccc_quirk *quirk);
> +#else
> +static inline void __arm_smccc_smc(unsigned long a0, unsigned long a1,
> +			unsigned long a2, unsigned long a3, unsigned long a4,
> +			unsigned long a5, unsigned long a6, unsigned long a7,
> +			struct arm_smccc_res *res, struct arm_smccc_quirk *quirk)
> +{
> +	*res = (struct arm_smccc_res){};
> +}
> +#endif
>  
>  /**
>   * __arm_smccc_hvc() - make HVC calls
> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
> index c0475d1c9885..81cad9e1e412 100644
> --- a/include/linux/qcom_scm.h
> +++ b/include/linux/qcom_scm.h
> @@ -61,7 +61,6 @@ enum qcom_scm_ice_cipher {
>  #define QCOM_SCM_PERM_RW (QCOM_SCM_PERM_READ | QCOM_SCM_PERM_WRITE)
>  #define QCOM_SCM_PERM_RWX (QCOM_SCM_PERM_RW | QCOM_SCM_PERM_EXEC)
>  
> -#if IS_ENABLED(CONFIG_QCOM_SCM)
>  extern bool qcom_scm_is_available(void);
>  
>  extern int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus);
> @@ -115,74 +114,4 @@ extern int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
>  extern int qcom_scm_lmh_profile_change(u32 profile_id);
>  extern bool qcom_scm_lmh_dcvsh_available(void);
>  
> -#else
> -
> -#include <linux/errno.h>
> -
> -static inline bool qcom_scm_is_available(void) { return false; }
> -
> -static inline int qcom_scm_set_cold_boot_addr(void *entry,
> -		const cpumask_t *cpus) { return -ENODEV; }
> -static inline int qcom_scm_set_warm_boot_addr(void *entry,
> -		const cpumask_t *cpus) { return -ENODEV; }
> -static inline void qcom_scm_cpu_power_down(u32 flags) {}
> -static inline u32 qcom_scm_set_remote_state(u32 state,u32 id)
> -		{ return -ENODEV; }
> -
> -static inline int qcom_scm_pas_init_image(u32 peripheral, const void *metadata,
> -		size_t size) { return -ENODEV; }
> -static inline int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr,
> -		phys_addr_t size) { return -ENODEV; }
> -static inline int qcom_scm_pas_auth_and_reset(u32 peripheral)
> -		{ return -ENODEV; }
> -static inline int qcom_scm_pas_shutdown(u32 peripheral) { return -ENODEV; }
> -static inline bool qcom_scm_pas_supported(u32 peripheral) { return false; }
> -
> -static inline int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val)
> -		{ return -ENODEV; }
> -static inline int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
> -		{ return -ENODEV; }
> -
> -static inline bool qcom_scm_restore_sec_cfg_available(void) { return false; }
> -static inline int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare)
> -		{ return -ENODEV; }
> -static inline int qcom_scm_iommu_secure_ptbl_size(u32 spare, size_t *size)
> -		{ return -ENODEV; }
> -static inline int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare)
> -		{ return -ENODEV; }
> -extern inline int qcom_scm_mem_protect_video_var(u32 cp_start, u32 cp_size,
> -						 u32 cp_nonpixel_start,
> -						 u32 cp_nonpixel_size)
> -		{ return -ENODEV; }
> -static inline int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> -		unsigned int *src, const struct qcom_scm_vmperm *newvm,
> -		unsigned int dest_cnt) { return -ENODEV; }
> -
> -static inline bool qcom_scm_ocmem_lock_available(void) { return false; }
> -static inline int qcom_scm_ocmem_lock(enum qcom_scm_ocmem_client id, u32 offset,
> -		u32 size, u32 mode) { return -ENODEV; }
> -static inline int qcom_scm_ocmem_unlock(enum qcom_scm_ocmem_client id,
> -		u32 offset, u32 size) { return -ENODEV; }
> -
> -static inline bool qcom_scm_ice_available(void) { return false; }
> -static inline int qcom_scm_ice_invalidate_key(u32 index) { return -ENODEV; }
> -static inline int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
> -				       enum qcom_scm_ice_cipher cipher,
> -				       u32 data_unit_size) { return -ENODEV; }
> -
> -static inline bool qcom_scm_hdcp_available(void) { return false; }
> -static inline int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt,
> -		u32 *resp) { return -ENODEV; }
> -
> -static inline int qcom_scm_qsmmu500_wait_safe_toggle(bool en)
> -		{ return -ENODEV; }
> -
> -static inline int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
> -				     u64 limit_node, u32 node_id, u64 version)
> -		{ return -ENODEV; }
> -
> -static inline int qcom_scm_lmh_profile_change(u32 profile_id) { return -ENODEV; }
> -
> -static inline bool qcom_scm_lmh_dcvsh_available(void) { return -ENODEV; }
> -#endif
>  #endif
> -- 
> 2.29.2
> 

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

[Arnd Bergmann]

On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
> On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> >  - To avoid a circular dependency chain involving RESET_CONTROLLER
> >    and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
> >    the latter one to 'select'.
>
> Can you please help me understand why this is part of the same patch?

This can be done as a preparatory patch if we decide to do it this way,
for the review it seemed better to spell out that this is required.

I still hope that we can avoid adding another 'select RESET_CONTROLLER'
if someone can figure out what to do instead.

The problem here is that QCOM_SCM selects RESET_CONTROLLER,
and turning that into 'depends on' would in turn mean that any driver that
wants to select QCOM_SCM would have to have the same RESET_CONTROLLER
dependency.

An easier option might be to find a way to build QCOM_SCM without
RESET_CONTROLLER for compile testing purposes. I don't know
what would break from that.

     Arnd

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

[Bjorn Andersson]

On Mon 27 Sep 13:15 PDT 2021, Arnd Bergmann wrote:

> On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> > On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@arndb.de>
> > >
> > >  - To avoid a circular dependency chain involving RESET_CONTROLLER
> > >    and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
> > >    the latter one to 'select'.
> >
> > Can you please help me understand why this is part of the same patch?
> 
> This can be done as a preparatory patch if we decide to do it this way,
> for the review it seemed better to spell out that this is required.
> 
> I still hope that we can avoid adding another 'select RESET_CONTROLLER'
> if someone can figure out what to do instead.
> 

Okay, thanks.

> The problem here is that QCOM_SCM selects RESET_CONTROLLER,
> and turning that into 'depends on' would in turn mean that any driver that
> wants to select QCOM_SCM would have to have the same RESET_CONTROLLER
> dependency.
> 

Right, and that will just be another thing we'll get wrong across the
tree.

> An easier option might be to find a way to build QCOM_SCM without
> RESET_CONTROLLER for compile testing purposes. I don't know
> what would break from that.
> 

Afaict the reset API is properly stubbed and RESET_CONTROLLER is a bool,
so I think we can simply drop the "select" and the kernel will still
compile fine in all combinations.

When it comes to runtime, we currently select RESET_CONTROLLER from the
Qualcomm common clocks. If that is dropped (why would it...) it seems
possible to build a custom kernel for msm8916 that we can boot and miss
the stubbed out "mss restart" reset line from the SCM.


So, let's just drop the select RESET_CONTROLLER from SCM for now.

Regards,
Bjorn

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

[Arnd Bergmann]

On Mon, Sep 27, 2021 at 10:42 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
> On Mon 27 Sep 13:15 PDT 2021, Arnd Bergmann wrote:
> > On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson <bjorn.andersson@linaro.org> wrote:
> >
> > An easier option might be to find a way to build QCOM_SCM without
> > RESET_CONTROLLER for compile testing purposes. I don't know
> > what would break from that.
> >
>
> Afaict the reset API is properly stubbed and RESET_CONTROLLER is a bool,
> so I think we can simply drop the "select" and the kernel will still
> compile fine in all combinations.
>
> When it comes to runtime, we currently select RESET_CONTROLLER from the
> Qualcomm common clocks. If that is dropped (why would it...) it seems
> possible to build a custom kernel for msm8916 that we can boot and miss
> the stubbed out "mss restart" reset line from the SCM.
>
>
> So, let's just drop the select RESET_CONTROLLER from SCM for now.

Ok, I've made that change locally, giving it more time on the randconfig
build box now.

       Arnd

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

[Kalle Valo]

Arnd Bergmann <arnd@kernel.org> 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
>>>> 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>

[...]

> 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 <kvalo@codeaurora.org>

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

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

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

[Arnd Bergmann]

On Tue, Sep 28, 2021 at 9:05 AM Kalle Valo <kvalo@codeaurora.org> wrote:
> Arnd Bergmann <arnd@kernel.org> writes:
> > 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 <kvalo@codeaurora.org>
>
> --
> 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

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

[Will Deacon]

On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> 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
> >>> 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

I don't want to get in the way of this patch because I'm also tired of the
randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
a wide variety of (non-qcom) SoCs and so it seems a shame to require the
QCOM_SCM code to be included for all of those when it's not strictly needed
at all.

Will

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

[Arnd Bergmann]

On Wed, Sep 29, 2021 at 11:51 AM Will Deacon <will@kernel.org> wrote:
> On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> >
> > 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
>
> I don't want to get in the way of this patch because I'm also tired of the
> randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> QCOM_SCM code to be included for all of those when it's not strictly needed
> at all.

Good point, I agree that needs to be fixed. I think this additional
change should do the trick:

--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -308,7 +308,6 @@ config APPLE_DART
 config ARM_SMMU
        tristate "ARM Ltd. System MMU (SMMU) Support"
        depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
-       select QCOM_SCM
        select IOMMU_API
        select IOMMU_IO_PGTABLE_LPAE
        select ARM_DMA_USE_IOMMU if ARM
@@ -438,7 +437,7 @@ config QCOM_IOMMU
        # Note: iommu drivers cannot (yet?) be built as modules
        bool "Qualcomm IOMMU Support"
        depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
-       depends on QCOM_SCM=y
+       select QCOM_SCM
        select IOMMU_API
        select IOMMU_IO_PGTABLE_LPAE
        select ARM_DMA_USE_IOMMU

I'll see if that causes any problems for the randconfig builds.

       Arnd

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

[Bjorn Andersson]

On Wed 29 Sep 05:04 CDT 2021, Arnd Bergmann wrote:

> On Wed, Sep 29, 2021 at 11:51 AM Will Deacon <will@kernel.org> wrote:
> > On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> > >
> > > 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
> >
> > I don't want to get in the way of this patch because I'm also tired of the
> > randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> > a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> > QCOM_SCM code to be included for all of those when it's not strictly needed
> > at all.
> 
> Good point, I agree that needs to be fixed. I think this additional
> change should do the trick:
> 

ARM_SMMU and QCOM_IOMMU are two separate implementations and both uses
QCOM_SCM. So both of them should select QCOM_SCM.

"Unfortunately" the Qualcomm portion of ARM_SMMU is builtin
unconditionally, so going with something like select QCOM_SCM if
ARCH_QCOM would still require the stubs in qcom_scm.h.

Regards,
Bjorn

> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -308,7 +308,6 @@ config APPLE_DART
>  config ARM_SMMU
>         tristate "ARM Ltd. System MMU (SMMU) Support"
>         depends on ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> -       select QCOM_SCM
>         select IOMMU_API
>         select IOMMU_IO_PGTABLE_LPAE
>         select ARM_DMA_USE_IOMMU if ARM
> @@ -438,7 +437,7 @@ config QCOM_IOMMU
>         # Note: iommu drivers cannot (yet?) be built as modules
>         bool "Qualcomm IOMMU Support"
>         depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
> -       depends on QCOM_SCM=y
> +       select QCOM_SCM
>         select IOMMU_API
>         select IOMMU_IO_PGTABLE_LPAE
>         select ARM_DMA_USE_IOMMU
> 
> I'll see if that causes any problems for the randconfig builds.
> 
>        Arnd

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

[Arnd Bergmann]

On Wed, Sep 29, 2021 at 4:46 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> On Wed 29 Sep 05:04 CDT 2021, Arnd Bergmann wrote:
>
> > On Wed, Sep 29, 2021 at 11:51 AM Will Deacon <will@kernel.org> wrote:
> > > On Mon, Sep 27, 2021 at 05:22:13PM +0200, Arnd Bergmann wrote:
> > > >
> > > > 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
> > >
> > > I don't want to get in the way of this patch because I'm also tired of the
> > > randconfig failures caused by QCOM_SCM. However, ARM_SMMU is applicable to
> > > a wide variety of (non-qcom) SoCs and so it seems a shame to require the
> > > QCOM_SCM code to be included for all of those when it's not strictly needed
> > > at all.
> >
> > Good point, I agree that needs to be fixed. I think this additional
> > change should do the trick:
> >
>
> ARM_SMMU and QCOM_IOMMU are two separate implementations and both uses
> QCOM_SCM. So both of them should select QCOM_SCM.

Right, I figured that out later as well.

> "Unfortunately" the Qualcomm portion of ARM_SMMU is builtin
> unconditionally, so going with something like select QCOM_SCM if
> ARCH_QCOM would still require the stubs in qcom_scm.h.

Yes, sounds good. I also noticed that I still need one hack in there
if I do this:

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 55690af1b25d..36c304a8fc9b 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -427,6 +427,9 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct
arm_smmu_device *smmu)
 {
        const struct device_node *np = smmu->dev->of_node;

+       if (!IS_ENABLED(CONFIG_QCOM_SCM))
+               return ERR_PTR(-ENXIO);
+
 #ifdef CONFIG_ACPI
        if (np == NULL) {
                /* Match platform for ACPI boot */


Otherwise it still breaks with ARM_SMMU=y and QCOM_SCM=m.

Splitting out the qualcomm portion of the arm_smmu driver using
a separate 'bool' symbol should also work, if  you prefer that
and can suggest a name and help text for that symbol. It would
look like

diff --git a/drivers/iommu/arm/arm-smmu/Makefile
b/drivers/iommu/arm/arm-smmu/Makefile
index e240a7bcf310..b0cc01aa20c9 100644
--- a/drivers/iommu/arm/arm-smmu/Makefile
+++ b/drivers/iommu/arm/arm-smmu/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_QCOM_IOMMU) += qcom_iommu.o
 obj-$(CONFIG_ARM_SMMU) += arm_smmu.o
-arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o arm-smmu-qcom.o
+arm_smmu-objs += arm-smmu.o arm-smmu-impl.o arm-smmu-nvidia.o
+arm_smmu-$(CONFIG_ARM_SMMU_QCOM) += arm-smmu-qcom.o
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
index 9f465e146799..2c25cce38060 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-impl.c
@@ -215,7 +215,8 @@ struct arm_smmu_device *arm_smmu_impl_init(struct
arm_smmu_device *smmu)
            of_device_is_compatible(np, "nvidia,tegra186-smmu"))
                return nvidia_smmu_impl_init(smmu);

-       smmu = qcom_smmu_impl_init(smmu);
+       if (IS_ENABLED(CONFIG_ARM_SMMU_QCOM))
+               smmu = qcom_smmu_impl_init(smmu);

        if (of_device_is_compatible(np, "marvell,ap806-smmu-500"))
                smmu->impl = &mrvl_mmu500_impl;



       Arnd