[PATCH v2 2/2] dt-bindings: xen: Add xen,scmi-devid property description for SCMI

[Oleksii Moisieiev]

Document xen,scmi-devid property for the devices, using SCMI protocol
to work with clocks/resets/power-domains etc. This property is intended
to set the device_id, which should be used to manage device permissions
in the Firmware. Device permissions management described in DEN 0056,
Section 4.2.2.10 [0].

This property is used by Xen hypervisor, which works as trusted Agent, to
set permissions for the devices, passed-through to the Guest Domains,
which are non-trusted Agents. Trusted and non-trusted Agent terms described
in Section 4.1.1 [0].

[0] https://developer.arm.com/documentation/den0056/latest

Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx>
---
 .../bindings/firmware/xen,scmi-devid.yaml     | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml

diff --git a/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml b/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml
new file mode 100644
index 000000000000..49dc9951b54d
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/xen,scmi-devid.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2022 EPAM Systems.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/firmware/xen,scmi-devid.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xen SCMI (System Control and Management Interface) Device ID binding
+
+maintainers:
+  - Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx>
+
+select: true
+
+description: |
+  SCMI device_id property is intended to set the device id, needed to manage
+  the device permissions via SCMI protocol in the firmware. The device_id
+  should match device ids, defined in the firmware so the device permissions
+  can be requested by sending BASE_SET_DEVICE_PERMISSIONS (see 4.2.2.10 of [0]).
+
+  This property is used by Xen hypervisor to set the device permissions for
+  the Guest Domains. Where Xen is trusted Agent and Guest Domains are
+  non-trusted Agents.
+
+  [0] https://developer.arm.com/documentation/den0056/latest
+
+properties:
+  xen,scmi-devid:
+    description: Identifier of the device, matching device id, defined in
+      the firmware.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+additionalProperties: true
+
+examples:
+  - |
+    ohci1: usb@ee0a0000 {
+        /* ... */
+        reg = <0xee0a0000 0x100>;
+        xen,scmi-devid = <11>;
+        clocks = <&scmi_clock 4>;
+    };
-- 
2.27.0