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

From: Arnd Bergmann <[email-masked]>
Date: Mon, 27 Sep 2021 17:22:13 +0200

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]>
---
 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