* Re: [PATCH v3 2/3] dt-bindings: firmware: add mbedtee,tee binding
[not found] ` <20260720073558.799755-3-xing.xl.loong@gmail.com>
@ 2026-07-31 20:19 ` Rob Herring via OP-TEE
0 siblings, 0 replies; 2+ messages in thread
From: Rob Herring via OP-TEE @ 2026-07-31 20:19 UTC (permalink / raw)
To: Xing Loong
Cc: Jens Wiklander, Krzysztof Kozlowski, Conor Dooley, Sumit Garg,
op-tee, devicetree, linux-riscv, linux-kernel
On Mon, Jul 20, 2026 at 03:35:56PM +0800, Xing Loong wrote:
> MbedTEE is a Trusted Execution Environment for embedded
> systems (https://github.com/mbedtee). It communicates with
> the REE via shared-memory ring buffers using a fixed RPC
> protocol. Two platform configurations are supported:
>
> - ARM/AArch64 (TrustZone, SMC): two reserved-memory
> regions (t2r-ring and t2r-shm) plus a GIC SPI edge
> interrupt for TEE-to-REE notifications.
> - RISC-V (IMSIC): three reserved-memory regions, adding
> r2t-ring for REE-to-TEE command submissions; no
> interrupts property (T2R notifications use IMSIC MSI
> allocated at runtime).
>
> Signed-off-by: Xing Loong <xing.xl.loong@gmail.com>
> ---
> Changes in v3:
> - Drop all phandle stub nodes from examples.
> - Remove redundant required: - interrupts from then branch.
> - Simplify title and description.
>
> Changes in v2:
> - Fix DT binding review comments from Krzysztof Kozlowski:
> - Drop $nodename, "YAML devicetree binding" wording, property descriptions
> - Rename compatible string to mbedtee,tee
> - Rename memory regions: rpc-t2r-ring -> t2r-ring, rpc-t2r-shm -> t2r-shm,
> rpc-r2t-ring -> r2t-ring
> - Add memory-region / memory-region-names to required
> - Simplify allOf constraints (drop redundant else-branch items)
> - Rewrite description to describe hardware/firmware, not the binding or driver
> - Drop all irrelevant platform nodes (gic, cpus, reserved-memory)
> - Add maxItems: 1 constraint to interrupts property (Sashiko AI review)
>
> ---
>
> .../bindings/firmware/mbedtee,tee.yaml | 109 ++++++++++++++++++
> 1 file changed, 109 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml
>
> diff --git a/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml
> new file mode 100644
> index 0000000..a8f1201
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml
> @@ -0,0 +1,109 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/mbedtee,tee.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MbedTEE
> +
> +maintainers:
> + - Xing Loong <xing.xl.loong@gmail.com>
> +
> +description: |
> + MbedTEE is a Trusted Execution Environment for embedded systems.
> + It communicates with the REE (Linux) via shared-memory ring
> + buffers using a fixed RPC protocol.
> +
> + We're using "mbedtee" as the vendor prefix for the open-source TEE
> + project at https://github.com/mbedtee.
> +
> + The REE and TEE CPUs sharing the RPC memory must be in a
> + hardware-coherent domain.
> +
> + Two or three reserved-memory regions are required:
> + t2r-ring: ring buffer for TEE-to-REE notifications
> + t2r-shm: shared memory for TEE-to-REE RPC payloads
> + r2t-ring: ring buffer for REE-to-TEE command submissions (RISC-V)
Put any details about specific properties with the property schema.
> +
> + On ARM the transport uses SMC and a GIC SPI interrupt. On RISC-V
> + the transport uses shared-memory rings and IMSIC MSI; the TEE
> + polls r2t-ring for commands from the REE.
> +
> +properties:
> + compatible:
> + const: mbedtee,tee
> +
> + interrupts:
> + maxItems: 1
> +
> + msi-parent:
> + maxItems: 1
> +
> + memory-region:
> + minItems: 2
> + maxItems: 3
> +
> + memory-region-names:
> + minItems: 2
> + maxItems: 3
> + items:
> + enum:
> + - t2r-ring
> + - t2r-shm
> + - r2t-ring
Needs to define the order as sashiko points out. The order doesn't
change, so it doesn't need to be defined in the if/then schemas.
> +
> +required:
> + - compatible
> + - memory-region
> + - memory-region-names
> +
> +allOf:
> + - if:
> + required:
> + - interrupts
> + then:
> + properties:
> + msi-parent: false
> + memory-region:
> + maxItems: 2
> + memory-region-names:
> + items:
> + - const: t2r-ring
> + - const: t2r-shm
Just 'maxItems: 2'
> + else:
> + required:
> + - msi-parent
> + properties:
> + interrupts: false
> + memory-region:
> + minItems: 3
> + memory-region-names:
> + items:
> + - const: t2r-ring
> + - const: t2r-shm
> + - const: r2t-ring
Just 'minItems: 3'
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> + firmware {
> + mbedtee {
> + compatible = "mbedtee,tee";
> + interrupts = <GIC_SPI 72 IRQ_TYPE_EDGE_RISING>;
> + memory-region = <&t2r_ring>, <&t2r_shm>;
> + memory-region-names = "t2r-ring", "t2r-shm";
> + };
> + };
> +
> + - |
> + firmware {
> + mbedtee {
> + compatible = "mbedtee,tee";
> + msi-parent = <&imsic>;
> + memory-region = <&t2r_ring>, <&t2r_shm>, <&r2t_ring>;
> + memory-region-names = "t2r-ring", "t2r-shm", "r2t-ring";
> + };
> + };
> --
> 2.43.0
>
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