tree ce2c67613d9d7dd3a5f66c7515a1c45c92f1e955
parent 9121478ee6f2aee381f8fe49d8997d43527d351a
author Etienne Carriere <etienne.carriere@linaro.org> 1654013356 +0200
committer Tom Rini <trini@konsulko.com> 1656004375 -0400

firmware: scmi: optee: use TEE shared memory for SCMI messages

Changes implementation when using TEE dynamically allocated shared
memory to synchronize with the Linux implementation where the legacy
SMT protocol cannot be used with such memory since it is expected from
device mapped memory whereas OP-TEE shared memory is cached and
hence should not be accessed using memcpy_toio()/memcpy_fromio().

This change implements the MSG shared memory protocol introduced
in Linux [1]. The protocol uses a simplified SMT header of 32bit
named MSG_SMT to carry SCMI protocol information and uses side channel
means to carry exchanged buffer size information, as TEE invocation API
parameters when used in the SCMI OP-TEE transport.

Link: [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f301bba0ca7392d16a6ea4f1d264a91f1fadea1a
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>