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@xxxxxxxxxx/
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
---
Changes v2 -> v3:
* Use "const" instead of "enum" for singleton compatible string.
.../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 <thiruan@xxxxxxxxxxxxx>
+ - Sasha Levin <sashal@xxxxxxxxxx>
+
+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>;
+ };
--
2.40.1
