This series introduces a generic TEE bus driver concept for TEE based kernel drivers which would like to communicate with TEE based devices/ services.
Patch #1 adds TEE bus concept where devices/services are identified via Universally Unique Identifier (UUID) and drivers register a table of device UUIDs which they can support. This concept also allows for device enumeration to be specific to corresponding TEE implementation like OP-TEE etc.
Patch #2 adds supp_nowait flag for non-blocking requests arising via TEE internal client interface.
Patch #3 adds TEE bus device enumeration support for OP-TEE. OP-TEE provides a pseudo TA to enumerate TAs which can act as devices/services for TEE bus.
Patch #4 adds OP-TEE based hwrng driver which act as TEE bus driver. On ARM SoC's with TrustZone enabled, peripherals like entropy sources might not be accessible to normal world (linux in this case) and rather accessible to secure world (OP-TEE in this case) only. So this driver aims to provides a generic interface to OP-TEE based random number generator service.
Example case is Developerbox based on Socionext's Synquacer SoC [1] which provides 7 thermal sensors accessible from secure world only which could be used as entropy sources (thermal/measurement noise).
[1] https://www.96boards.org/product/developerbox/
Changes in v4:
1. Use typedef instead of single member tee_client_device_id struct. 2. Incorporate TEE bus nitpicks.
Changes in v3:
1. Fixed bus error path in Patch #1. 2. Reversed order of Patch #2 and #3. 3. Fixed miscellaneous syntax comments and memory leak. 4. Added comments in Patch #2 for supp_nowait flag.
Changes in v2:
Based on review comments, the scope of this series has increased as follows:
1. Added TEE bus driver framework. 2. Added OP-TEE based device enumeration. 3. Register optee-rng driver as TEE bus driver. 4. Removed DT dependency for optee-rng device UUID. 5. Added supp_nowait flag.
Sumit Garg (4): tee: add bus driver framework for TEE based devices tee: add supp_nowait flag in tee_context struct tee: optee: add TEE bus device enumeration support hwrng: add OP-TEE based rng driver
MAINTAINERS | 5 + drivers/char/hw_random/Kconfig | 15 ++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/optee-rng.c | 272 +++++++++++++++++++++++++++++++++++++ drivers/tee/optee/Makefile | 1 + drivers/tee/optee/core.c | 4 + drivers/tee/optee/device.c | 153 +++++++++++++++++++++ drivers/tee/optee/optee_private.h | 3 + drivers/tee/optee/supp.c | 10 +- drivers/tee/tee_core.c | 58 +++++++- include/linux/tee_drv.h | 43 +++++- 11 files changed, 559 insertions(+), 6 deletions(-) create mode 100644 drivers/char/hw_random/optee-rng.c create mode 100644 drivers/tee/optee/device.c