Commit 3f4cc70d authored by Lukas Wunner's avatar Lukas Wunner Committed by Rob Herring
Browse files

dt-bindings: tpm: Document Microsoft fTPM bindings 

A driver for Microsoft's firmware-based Trusted Platform Module (fTPM)
was merged with commit 09e57483 ("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: default avatarLukas Wunner <lukas@wunner.de>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/99523409eb5aec9276055ff358ae6f2ceb10be6d.1702806810.git.lukas@wunner.de


Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent cd6366c0

Documentation/devicetree/bindings/tpm/microsoft,ftpm.yaml

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# 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 <thiruan@microsoft.com>

  - Sasha Levin <sashal@kernel.org>



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>;

    };