u-boot/doc/README.tee

2 TEE uclass
5 This document describes the TEE uclass in U-Boot
7 A TEE (Trusted Execution Environment) is a trusted OS running in some
9 secure co-processor etc. A TEE driver handles the details needed to
10 communicate with the TEE.
14 - Registration of TEE drivers
16 - Managing shared memory between U-Boot and the TEE
18 - Providing a generic API to the TEE
20 The TEE interface
23 include/tee.h defines the generic interface to a TEE.
25 A client finds the TEE device via tee_find_device(). Other important functions
26 when interfacing with a TEE are:
29   memory objects often needed when communicating with the TEE.
31 - tee_get_version() lets the client know which the capabilities of the TEE
40 Much of the communication between clients and the TEE is opaque to the
42 clients, forward them to the TEE and send back the results.
44 OP-TEE driver
47 The OP-TEE driver handles OP-TEE [1] based TEEs. Currently it is only the ARM
48 TrustZone based OP-TEE solution that is supported.
50 Lowest level of communication with OP-TEE builds on ARM SMC Calling
51 Convention (SMCCC) [2], which is the foundation for OP-TEE's SMC interface
52 [3] used internally by the driver. Stacked on top of that is OP-TEE Message
55 OP-TEE SMC interface provides the basic functions required by SMCCC and some
56 additional functions specific for OP-TEE. The most interesting functions are:
61 - OPTEE_SMC_CALL_GET_OS_UUID returns the particular OP-TEE implementation, used
62   to tell, for instance, a TrustZone OP-TEE apart from an OP-TEE running on a
65 - OPTEE_SMC_CALL_WITH_ARG drives the OP-TEE message protocol
67 - OPTEE_SMC_GET_SHM_CONFIG lets the driver and OP-TEE agree on which memory
68   range to used for shared memory between Linux and OP-TEE.
70 The GlobalPlatform TEE Client API [5] is implemented on top of the generic
71 TEE API.
74 OP-TEE architecture:
86                  | TEE        |           | TEE Internal|
89                  | OP-TEE     |           | OP-TEE      |
92                  |             OP-TEE MSG               |
103 [1] https://github.com/OP-TEE/optee_os
112     "TEE Client API Specification v1.0" and click download.