From: Marouene Boubakri <marouene.boubakri@oss.nxp.com>

The OP-TEE driver reaches OP-TEE through the SMC ABI or the FF-A ABI,
both specific to Arm, yet builds both unconditionally together with the
SMC Calling Convention definitions they rely on: ffa_abi.c is always
compiled and only its registration is conditioned on
IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT), and optee_private.h includes
<linux/arm-smccc.h> and defines the SMC and FF-A specific types for
every file of the driver. This is fine as long as the driver depends on
HAVE_ARM_SMCCC, but it keeps the driver from being built for an
architecture without SMCCC, such as RISC-V.

Build smc_abi.c only when HAVE_ARM_SMCCC is set and ffa_abi.c only when
the FF-A transport is enabled, and provide stubs for their registration
otherwise, so that it fails with -EOPNOTSUPP as the FF-A ABI already
does when the FF-A transport is not reachable. Keep the SMCCC header,
the SMC invoke function type, the SMC and FF-A specific structures and
the SMC RPC register parameters in optee_private.h under the same
conditions, and drop the unused <linux/arm-smccc.h> include from
notif.c.

Make OPTEE depend on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT, as it
already does for RPMB, so that the driver is limited to a module when
the FF-A transport is one, rather than built in without FF-A support.
ffa_abi.c is thus built exactly when the FF-A transport is reachable
from the driver, and the IS_REACHABLE() checks in
optee_ffa_abi_register() and optee_ffa_abi_unregister() are always
true, so drop them.

OPTEE still depends on HAVE_ARM_SMCCC, so smc_abi.c is still always
built. The only visible change is that OPTEE=y can no longer be
combined with ARM_FFA_TRANSPORT=m: such a configuration now resolves to
OPTEE=m, with the FF-A ABI available.

Signed-off-by: Marouene Boubakri <marouene.boubakri@oss.nxp.com>
---
Changes in v4:
- Make OPTEE depend on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT so that
  the driver is limited to =m when the FF-A transport is =m (Jens).
- Update the commit message accordingly.
v3: https://lore.kernel.org/all/20260922131735.524635-1-marouene.boubakri@oss.nxp.com/

Changes in v3:
- Dropped the RPMI ABI placeholder and the RISC-V enablement patches,
  this is now a single patch (Jens).
- Key the FF-A parts of optee_private.h on IS_REACHABLE() instead of
  IS_ENABLED(): with OPTEE=y and ARM_FFA_TRANSPORT=m kbuild drops
  ffa_abi.o from the built-in optee.o while optee_ffa_abi_register()
  was still declared, which does not link.
- Drop the now always true IS_REACHABLE() checks in
  optee_ffa_abi_register() and optee_ffa_abi_unregister().
- Describe the current FF-A conditional compilation accurately in the
  commit message.
- Posted as a new thread with a proper subject prefix.
v2: https://lore.kernel.org/op-tee/20260915020235.507302-2-marouene.boubakri@oss.nxp.com/

Changes in v2:
- No code change, the testing section of the cover letter was completed.
v1: https://lore.kernel.org/op-tee/20260914175435.118303-2-marouene.boubakri@oss.nxp.com/
 drivers/tee/optee/Kconfig         |  1 +
 drivers/tee/optee/Makefile        |  4 ++--
 drivers/tee/optee/ffa_abi.c       |  8 ++-----
 drivers/tee/optee/notif.c         |  1 -
 drivers/tee/optee/optee_private.h | 39 ++++++++++++++++++++++++++++++-
 5 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
index 50d2051..891dac6 100644
--- a/drivers/tee/optee/Kconfig
+++ b/drivers/tee/optee/Kconfig
@@ -5,6 +5,7 @@ config OPTEE
 	depends on HAVE_ARM_SMCCC
 	depends on MMU
 	depends on RPMB || !RPMB
+	depends on ARM_FFA_TRANSPORT || !ARM_FFA_TRANSPORT
 	help
 	  This implements the OP-TEE Trusted Execution Environment (TEE)
 	  driver.
diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
index ad7049c..183cdde 100644
--- a/drivers/tee/optee/Makefile
+++ b/drivers/tee/optee/Makefile
@@ -7,8 +7,8 @@ optee-objs += rpc.o
 optee-objs += protmem.o
 optee-objs += supp.o
 optee-objs += device.o
-optee-objs += smc_abi.o
-optee-objs += ffa_abi.o
+optee-$(CONFIG_HAVE_ARM_SMCCC) += smc_abi.o
+optee-$(CONFIG_ARM_FFA_TRANSPORT) += ffa_abi.o
 
 # for tracing framework to find optee_trace.h
 CFLAGS_smc_abi.o := -I$(src)
diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
index 633715b..08236d8 100644
--- a/drivers/tee/optee/ffa_abi.c
+++ b/drivers/tee/optee/ffa_abi.c
@@ -1212,14 +1212,10 @@ static struct ffa_driver optee_ffa_driver = {
 
 int optee_ffa_abi_register(void)
 {
-	if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT))
-		return ffa_register(&optee_ffa_driver);
-	else
-		return -EOPNOTSUPP;
+	return ffa_register(&optee_ffa_driver);
 }
 
 void optee_ffa_abi_unregister(void)
 {
-	if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT))
-		ffa_unregister(&optee_ffa_driver);
+	ffa_unregister(&optee_ffa_driver);
 }
diff --git a/drivers/tee/optee/notif.c b/drivers/tee/optee/notif.c
index 6e85f2f..6801422 100644
--- a/drivers/tee/optee/notif.c
+++ b/drivers/tee/optee/notif.c
@@ -5,7 +5,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/arm-smccc.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index aefe1e6..02d6f79 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -6,7 +6,6 @@
 #ifndef OPTEE_PRIVATE_H
 #define OPTEE_PRIVATE_H
 
-#include <linux/arm-smccc.h>
 #include <linux/notifier.h>
 #include <linux/rhashtable.h>
 #include <linux/rpmb.h>
@@ -15,6 +14,10 @@
 #include <linux/types.h>
 #include "optee_msg.h"
 
+#ifdef CONFIG_HAVE_ARM_SMCCC
+#include <linux/arm-smccc.h>
+#endif
+
 #define DRIVER_NAME "optee"
 
 #define OPTEE_MAX_ARG_SIZE	1024
@@ -42,10 +45,12 @@
  */
 #define OPTEE_DEFAULT_MAX_NOTIF_VALUE	255
 
+#ifdef CONFIG_HAVE_ARM_SMCCC
 typedef void (optee_invoke_fn)(unsigned long, unsigned long, unsigned long,
 				unsigned long, unsigned long, unsigned long,
 				unsigned long, unsigned long,
 				struct arm_smccc_res *);
+#endif
 
 /**
  * struct optee_call_waiter - TEE entry may need to wait for a free TEE thread
@@ -119,6 +124,7 @@ struct optee_supp {
 	struct completion reqs_c;
 };
 
+#ifdef CONFIG_HAVE_ARM_SMCCC
 /**
  * struct optee_pcpu - per cpu notif private struct passed to work functions
  * @optee:	optee device reference
@@ -149,7 +155,9 @@ struct optee_smc {
 	struct work_struct notif_pcpu_work;
 	unsigned int notif_cpuhp_state;
 };
+#endif
 
+#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
 /**
  * struct optee_ffa -  FFA communication struct
  * @ffa_dev:		FFA device, contains the destination id, the id of
@@ -170,6 +178,7 @@ struct optee_ffa {
 	struct workqueue_struct *notif_wq;
 	struct work_struct notif_work;
 };
+#endif
 
 struct optee;
 
@@ -257,8 +266,12 @@ struct optee {
 	const struct optee_ops *ops;
 	struct tee_context *ctx;
 	union {
+#ifdef CONFIG_HAVE_ARM_SMCCC
 		struct optee_smc smc;
+#endif
+#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
 		struct optee_ffa ffa;
+#endif
 	};
 	struct optee_shm_arg_cache shm_arg_cache;
 	struct optee_call_queue call_queue;
@@ -290,6 +303,7 @@ struct optee_context_data {
 	struct list_head sess_list;
 };
 
+#ifdef CONFIG_HAVE_ARM_SMCCC
 struct optee_rpc_param {
 	u32	a0;
 	u32	a1;
@@ -300,6 +314,7 @@ struct optee_rpc_param {
 	u32	a6;
 	u32	a7;
 };
+#endif
 
 /* Holds context that is preserved during one STD call */
 struct optee_call_ctx {
@@ -422,9 +437,31 @@ static inline void reg_pair_from_64(u32 *reg0, u32 *reg1, u64 val)
 }
 
 /* Registration of the ABIs */
+#ifdef CONFIG_HAVE_ARM_SMCCC
 int optee_smc_abi_register(void);
 void optee_smc_abi_unregister(void);
+#else
+static inline int optee_smc_abi_register(void)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void optee_smc_abi_unregister(void)
+{
+}
+#endif
+#if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
 int optee_ffa_abi_register(void);
 void optee_ffa_abi_unregister(void);
+#else
+static inline int optee_ffa_abi_register(void)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void optee_ffa_abi_unregister(void)
+{
+}
+#endif
 
 #endif /*OPTEE_PRIVATE_H*/

base-commit: 827751b699b79a6e569983359c02dce67f81b94c
-- 
2.43.0