Re: [PATCH RFC 5/5] dt-bindings: tee: add RISC-V RPMI TEE transport

On Sat, Sep 12, 2026 at 3:45 PM Amirreza Zarrabi amirreza.zarrabi@oss.qualcomm.com wrote:

Add a device-tree binding for the OP-TEE RISC-V transport using the RPMI TEE service group over SBI MPXY.

Describe one mailbox channel per hart and an optional interrupt used as the availability doorbell for asynchronous notifications.

Add the binding to the existing OP-TEE MAINTAINERS entry.

Signed-off-by: Amirreza Zarrabi amirreza.zarrabi@oss.qualcomm.com

.../bindings/tee/riscv,rpmi-mpxy-tee.yaml | 65 ++++++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 66 insertions(+)

diff --git a/Documentation/devicetree/bindings/tee/riscv,rpmi-mpxy-tee.yaml b/Documentation/devicetree/bindings/tee/riscv,rpmi-mpxy-tee.yaml new file mode 100644 index 000000000000..8f6ff313fd42 --- /dev/null +++ b/Documentation/devicetree/bindings/tee/riscv,rpmi-mpxy-tee.yaml @@ -0,0 +1,65 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +# Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries. +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/tee/riscv,rpmi-mpxy-tee.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#

+title: RISC-V RPMI TEE service group based message proxy

+maintainers:

• • Amirreza Zarrabi amirreza.zarrabi@oss.qualcomm.com

+description: |

• The RISC-V Platform Management Interface (RPMI) [1] defines a messaging
• protocol which is modular and extensible. The supervisor software can
• send/receive RPMI messages via the SBI MPXY extension [2] or some dedicated
• supervisor-mode RPMI transport.
• The RPMI specification [1] defines a TEE service group which is the RISC-V
• analog of Arm FF-A: OP-TEE and the rich execution environment (REE, i.e.
• Linux) are peer endpoints and the RPMI framework (machine mode firmware)
• mediates every message. Entering OP-TEE on a hart runs it on that hart until
• it responds, so the SBI implementation provides one SBI MPXY channel per
• hart; all of them are listed, in hart order, on a single node.
• ===========================================
• References
• ===========================================
• [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)

•  https://github.com/riscv-non-isa/riscv-rpmi/releases
  

• [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)

•  https://github.com/riscv-non-isa/riscv-sbi-doc/releases
  

+properties:

• compatible:
• const: riscv,rpmi-mpxy-tee
• mboxes:
• minItems: 1
• description:

•  One SBI MPXY channel implementing the RPMI TEE service group per hart,
  

•  listed in the same order as the CPU nodes.
  

I am not sure why you need separate MPXY channel per hart. The MPXY shared memory is already per-hart whereas the MPXY channel will be doman specific for TEE.

Also, for this binding refererring to only mailbox channel is sufficient. The underlying mechanism to send RPMI messages is abstracted away by the mailbox controller driver.

• interrupts:
• maxItems: 1
• description:

•  Availability doorbell raised by OP-TEE to signal asynchronous
  

•  notifications over the RPMI TEE signal bus. Optional; when absent
  

•  asynchronous notification is disabled.
  

+required:

• • compatible
• • mboxes

+additionalProperties: false

+examples:

• • |
• tee {

•    compatible = "riscv,rpmi-mpxy-tee";
  

This must be "riscv,rpmi-tee" based on above comments.

•    mboxes = <&mpxy_mbox 0x10 0x0>, <&mpxy_mbox 0x11 0x0>;
  

Like mentioned above, only one mailbox channel is sufficient.

• };

+... diff --git a/MAINTAINERS b/MAINTAINERS index 207a6e2db70c..7d0e550085b2 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20577,6 +20577,7 @@ M: Jens Wiklander jenswi@kernel.org L: op-tee@lists.trustedfirmware.org (moderated for non-subscribers) S: Maintained F: Documentation/ABI/testing/sysfs-bus-optee-devices +F: Documentation/devicetree/bindings/tee/riscv,rpmi-mpxy-tee.yaml F: drivers/tee/optee/

OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER

-- 2.34.1

Regards, Anup