On Fri, 23 Feb 2024 at 15:23, Balint Dobszay <balint.dobszay@xxxxxxx> wrote: > > Add documentation for the Trusted Services TEE driver. > > Signed-off-by: Balint Dobszay <balint.dobszay@xxxxxxx> > --- > Documentation/tee/index.rst | 1 + > Documentation/tee/ts-tee.rst | 71 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 72 insertions(+) > create mode 100644 Documentation/tee/ts-tee.rst > Acked-by: Sumit Garg <sumit.garg@xxxxxxxxxx> -Sumit > diff --git a/Documentation/tee/index.rst b/Documentation/tee/index.rst > index a23bd08847e5..4be6e69d7837 100644 > --- a/Documentation/tee/index.rst > +++ b/Documentation/tee/index.rst > @@ -10,6 +10,7 @@ TEE Subsystem > tee > op-tee > amd-tee > + ts-tee > > .. only:: subproject and html > > diff --git a/Documentation/tee/ts-tee.rst b/Documentation/tee/ts-tee.rst > new file mode 100644 > index 000000000000..843e34422648 > --- /dev/null > +++ b/Documentation/tee/ts-tee.rst > @@ -0,0 +1,71 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +================================= > +TS-TEE (Trusted Services project) > +================================= > + > +This driver provides access to secure services implemented by Trusted Services. > + > +Trusted Services [1] is a TrustedFirmware.org project that provides a framework > +for developing and deploying device Root of Trust services in FF-A [2] S-EL0 > +Secure Partitions. The project hosts the reference implementation of the Arm > +Platform Security Architecture [3] for Arm A-profile devices. > + > +The FF-A Secure Partitions (SP) are accessible through the FF-A driver [4] which > +provides the low level communication for this driver. On top of that the Trusted > +Services RPC protocol is used [5]. To use the driver from user space a reference > +implementation is provided at [6], which is part of the Trusted Services client > +library called libts [7]. > + > +All Trusted Services (TS) SPs have the same FF-A UUID; it identifies the TS RPC > +protocol. A TS SP can host one or more services (e.g. PSA Crypto, PSA ITS, etc). > +A service is identified by its service UUID; the same type of service cannot be > +present twice in the same SP. During SP boot each service in the SP is assigned > +an "interface ID". This is just a short ID to simplify message addressing. > + > +The generic TEE design is to share memory at once with the Trusted OS, which can > +then be reused to communicate with multiple applications running on the Trusted > +OS. However, in case of FF-A, memory sharing works on an endpoint level, i.e. > +memory is shared with a specific SP. User space has to be able to separately > +share memory with each SP based on its endpoint ID; therefore a separate TEE > +device is registered for each discovered TS SP. Opening the SP corresponds to > +opening the TEE device and creating a TEE context. A TS SP hosts one or more > +services. Opening a service corresponds to opening a session in the given > +tee_context. > + > +Overview of a system with Trusted Services components:: > + > + User space Kernel space Secure world > + ~~~~~~~~~~ ~~~~~~~~~~~~ ~~~~~~~~~~~~ > + +--------+ +-------------+ > + | Client | | Trusted | > + +--------+ | Services SP | > + /\ +-------------+ > + || /\ > + || || > + || || > + \/ \/ > + +-------+ +----------+--------+ +-------------+ > + | libts | | TEE | TS-TEE | | FF-A SPMC | > + | | | subsys | driver | | + SPMD | > + +-------+----------------+----+-----+--------+-----------+-------------+ > + | Generic TEE API | | FF-A | TS RPC protocol | > + | IOCTL (TEE_IOC_*) | | driver | over FF-A | > + +-----------------------------+ +--------+-------------------------+ > + > +References > +========== > + > +[1] https://www.trustedfirmware.org/projects/trusted-services/ > + > +[2] https://developer.arm.com/documentation/den0077/ > + > +[3] https://www.arm.com/architecture/security-features/platform-security > + > +[4] drivers/firmware/arm_ffa/ > + > +[5] https://trusted-services.readthedocs.io/en/v1.0.0/developer/service-access-protocols.html#abi > + > +[6] https://git.trustedfirmware.org/TS/trusted-services.git/tree/components/rpc/ts_rpc/caller/linux/ts_rpc_caller_linux.c?h=v1.0.0 > + > +[7] https://git.trustedfirmware.org/TS/trusted-services.git/tree/deployments/libts/arm-linux/CMakeLists.txt?h=v1.0.0 > -- > 2.34.1 >
