[PATCHv3 0/4] OP-TEE I2C trampoline and associated tests

Jorge Ramirez-Ortiz jorge at foundries.io
Tue Jan 12 09:43:36 CET 2021

This patchset allows OP-TEE to communicate with I2C devices; a typical
use case would be servicing U-Boot requests that require underlying
cryptographic operations implemented by an I2C chip.

On a board fitted with the NXP SE050 I2C secure element, OP-TEE can
route some of the cryptographic operations it needs to that device (ie

Before the REE executes, OP-TEE would use its own I2C drivers to
communicate with the device on the bus; later on, once the REE is up,
accesses to the I2C bus should be coordinated with the REE to avoid
collisions. However instead of implementing such a synchronization
mechanism, this trampoline service permits OP-TEE to route those I2C
requests back to U-boot without then having to worry about collisions.

Lets suppose that U-Boot executes the trusted application Android
Verified Boot; when OP-TEE receives the request - and before executing
the application - it uses RSA to verify it. So on the back of the TA
function invocation, OP-TEE returns to U-boot with a sequence of RPC
calls requesting I2C transfers (check carefully the implementation in
do_call_with_arg(...) implemented in drivers/tee/optee/core.c and
notice the while loop)

When using sandbox testing, RPC is called directly to validate its
actual implementation; however as succintly described above, these
calls will always be originated in OP-TEE.

Igor Opaniuk (3):
  test: py: add pygit2 and pyelftools to requirements.txt
  drivers: tee: sandbox: add rpc test ta emulation
  test: dm: tee: extend with RPC test

Jorge Ramirez-Ortiz (1):
  drivers: tee: i2c trampoline driver

 drivers/tee/Makefile                     |   2 +
 drivers/tee/optee/Kconfig                |   9 ++
 drivers/tee/optee/Makefile               |   1 +
 drivers/tee/optee/i2c.c                  |  90 +++++++++++++++
 drivers/tee/optee/optee_msg.h            |  21 ++++
 drivers/tee/optee/optee_msg_supplicant.h |   5 +
 drivers/tee/optee/optee_private.h        |  17 +++
 drivers/tee/optee/supplicant.c           |   3 +
 drivers/tee/sandbox.c                    | 137 ++++++++++++++++++++++-
 include/tee/optee_ta_rpc_test.h          |  28 +++++
 test/dm/tee.c                            | 109 +++++++++++++++++-
 test/py/requirements.txt                 |   2 +
 12 files changed, 415 insertions(+), 9 deletions(-)
 create mode 100644 drivers/tee/optee/i2c.c
 create mode 100644 include/tee/optee_ta_rpc_test.h


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