From 3f4cc70d89099f8c40b6838a13ccac322dfa0a38 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sun, 17 Dec 2023 11:13:34 +0100 Subject: [PATCH] dt-bindings: tpm: Document Microsoft fTPM bindings A driver for Microsoft's firmware-based Trusted Platform Module (fTPM) was merged with commit 09e574831b27 ("tpm/tpm_ftpm_tee: A driver for firmware TPM running inside TEE"), but its devicetree bindings were not. This is the only remaining undocumented compatible string for a TPM, so add a DT schema based on the patch linked below. Link: https://lore.kernel.org/all/20190409184958.7476-2-sashal@kernel.org/ Signed-off-by: Lukas Wunner Reviewed-by: Rob Herring Link: https://lore.kernel.org/r/99523409eb5aec9276055ff358ae6f2ceb10be6d.1702806810.git.lukas@wunner.de Signed-off-by: Rob Herring --- .../bindings/tpm/microsoft,ftpm.yaml | 47 +++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 Documentation/devicetree/bindings/tpm/microsoft,ftpm.yaml diff --git a/Documentation/devicetree/bindings/tpm/microsoft,ftpm.yaml b/Documentation/devicetree/bindings/tpm/microsoft,ftpm.yaml new file mode 100644 index 000000000000..fdb81968f03d --- /dev/null +++ b/Documentation/devicetree/bindings/tpm/microsoft,ftpm.yaml @@ -0,0 +1,47 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/tpm/microsoft,ftpm.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Microsoft firmware-based Trusted Platform Module (fTPM) + +maintainers: + - Thirupathaiah Annapureddy + - Sasha Levin + +description: | + Commodity CPU architectures, such as ARM and Intel CPUs, have started to + offer trusted computing features in their CPUs aimed at displacing dedicated + trusted hardware. Unfortunately, these CPU architectures raise serious + challenges to building trusted systems because they omit providing secure + resources outside the CPU perimeter. + + Microsoft's firmware-based TPM 2.0 (fTPM) leverages ARM TrustZone to overcome + these challenges and provide software with security guarantees similar to + those of dedicated trusted hardware. + + https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ + https://github.com/Microsoft/ms-tpm-20-ref/tree/main/Samples/ARM32-FirmwareTPM + +properties: + compatible: + const: microsoft,ftpm + +required: + - compatible + - linux,sml-base + - linux,sml-size + +allOf: + - $ref: tpm-common.yaml# + +unevaluatedProperties: false + +examples: + - | + tpm { + compatible = "microsoft,ftpm"; + linux,sml-base = <0x0 0xc0000000>; + linux,sml-size = <0x10000>; + };