[PATCH RFC v2 0/8] tee: optee: add RPMI backend support on RISC-V

[Amirreza Zarrabi]

This series adds an RPMI backend to the OP-TEE driver for RISC-V.
It builds on the separately posted RPMI TEE transport series [1],
which provides service discovery, synchronous calls, memory parcels
and asynchronous signals.

This revision is effectively a full rewrite of the original RFC.
The generic RPMI transport has been separated from the OP-TEE backend,
and the backend has been reworked around the service bus and a new
OP-TEE control ABI.

Unlike v1, the OP-TEE backend no longer manages SBI MPXY mailbox
channels or implements RPMI TEE service-group operations directly.
It binds to the OP-TEE service UUID on the RPMI TEE bus and uses the
transport's public operations. No additional OP-TEE device-tree node
is required.

The backend reuses the common OP-TEE session, shared-memory, argument
cache, call queue and RPC infrastructure. Shared memory is represented
by RPMI parcel IDs and nonces. Yielding calls pass command and RPC
buffer ranges within a parcel and resume suspended execution using
an opaque token returned by OP-TEE.

The OP-TEE control ABI uses fixed-width little-endian messages carried
in TEE_CALL payloads rather than reproducing FF-A's register-based
message layout. Asynchronous notifications use an allocated TEE-to-REE
signal as a bottom-half doorbell, while ordinary logical notifications
continue through the common RPC path.

Matching OP-TEE OS support for this ABI has not yet been implemented.
This remains an RFC for review of the backend integration and the
Linux-to-OP-TEE protocol.

[1] RPMI TEE transport dependency:
https://lore.kernel.org/op-tee/20260928-riscv-rpmi-tee-abi-v1-0-04908b81d885@xxxxxxxxxxxxxxxx/

Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>
---
Changes in v2:
- Effectively rewrite the backend around the separately posted RPMI
  TEE transport and a new OP-TEE control ABI.
- Remove backend-owned per-hart mailbox channels and the OP-TEE-specific
  device-tree binding.
- Replace the register-like control payload with fixed-width messages,
  explicit command/RPC buffer ranges and opaque resume tokens.
- Add a parcel-reference parameter layout carrying the parcel ID,
  nonce, and 64-bit offset and size without changing parameter size.
- Make argument-offset support part of the baseline ABI and retain
  the common shared argument cache.
- Use a transport-allocated signal for asynchronous bottom-half
  notifications.
- Link to v1: https://lore.kernel.org/r/20260912-rpmi-tee-service-grp-dev-v1-0-1d1d35c2a859@xxxxxxxxxxxxxxxx

---
Amirreza Zarrabi (8):
      tee: optee: allow RPMI transport builds on RISC-V
      tee: optee: define the RPMI control and parcel-reference ABI
      tee: optee: add RPMI shared-memory and parameter support
      tee: optee: add RPMI dynamic shared-memory pool
      tee: optee: add RPMI RPC handling
      tee: optee: execute yielding RPMI calls
      tee: optee: bind RPMI services and negotiate backend capabilities
      tee: optee: support RPMI asynchronous notification doorbells

 drivers/tee/Kconfig               |    3 +-
 drivers/tee/optee/Kconfig         |    3 +-
 drivers/tee/optee/Makefile        |    1 +
 drivers/tee/optee/call.c          |    2 +
 drivers/tee/optee/core.c          |   10 +-
 drivers/tee/optee/optee_msg.h     |   38 +-
 drivers/tee/optee/optee_private.h |   54 +-
 drivers/tee/optee/optee_rpmi.h    |  234 ++++++++
 drivers/tee/optee/rpmi_abi.c      | 1059 +++++++++++++++++++++++++++++++++++++
 9 files changed, 1389 insertions(+), 15 deletions(-)
---
base-commit: bf1ee2bd5c2da8992f33c8950ef194aaff74ed6c
change-id: 20260912-rpmi-tee-service-grp-dev-b2ce2f63e0df

Best regards,
-- 
Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>