tee: optee: build the Arm-specific code only on Arm

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>
Signed-off-by: Jens Wiklander <jens.wiklander@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions