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 v4: - Move reserved-memory region descriptions into memory-region-names property (Rob) - Define memory-region-names item order at top level; keep per-branch name count constraints (maxItems: 2 / minItems: 3) (Rob)
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 $nodename, "YAML devicetree binding" wording, property descriptions - Rename compatible string to mbedtee,tee - Rename memory regions: rpc-t2r-ring -> t2r-ring, rpc-t2r-shm -> t2r-shm, rpc-r2t-ring -> r2t-ring - Add memory-region / memory-region-names to required - Simplify allOf constraints (drop redundant else-branch items) - Rewrite description to describe hardware/firmware, not the binding or driver - Drop all irrelevant platform nodes (gic, cpus, reserved-memory) - Add maxItems: 1 constraint to interrupts property (Sashiko AI review)
--- .../bindings/firmware/mbedtee,tee.yaml | 102 ++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml
diff --git a/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml new file mode 100644 index 0000000..a67ac43 --- /dev/null +++ b/Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml @@ -0,0 +1,102 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$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. 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: + description: | + 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) + minItems: 2 + items: + - const: t2r-ring + - const: t2r-shm + - const: r2t-ring + +required: + - compatible + - memory-region + - memory-region-names + +allOf: + - if: + required: + - interrupts + then: + properties: + msi-parent: false + memory-region: + maxItems: 2 + memory-region-names: + maxItems: 2 + else: + required: + - msi-parent + properties: + interrupts: false + memory-region: + minItems: 3 + memory-region-names: + 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"; + }; + };