On 27 Feb 2024, at 8:14, Sumit Garg wrote: > 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 Thanks, I'll apply the tag in the next version. Regards, Balint >> 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 >>
