[PATCH V1 4/6] dt-bindings: Add xen,dev-domid property description for xen-grant DMA ops

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Introduce Xen specific binding for the virtualized device (e.g. virtio)
to be used by Xen grant DMA-mapping layer in the subsequent commit.

This binding indicates that Xen grant mappings scheme needs to be
enabled for the device which DT node contains that property and specifies
the ID of Xen domain where the corresponding backend resides. The ID
(domid) is used as an argument to the grant mapping APIs.

This is needed for the option to restrict memory access using Xen grant
mappings to work which primary goal is to enable using virtio devices
in Xen guests.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
Changes RFC -> V1:
   - update commit subject/description and text in description
   - move to devicetree/bindings/arm/
---
 .../devicetree/bindings/arm/xen,dev-domid.yaml     | 37 ++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/xen,dev-domid.yaml

diff --git a/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml b/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml
new file mode 100644
index 00000000..ef0f747
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/xen,dev-domid.yaml
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/xen,dev-domid.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xen specific binding for the virtualized device (e.g. virtio)
+
+maintainers:
+  - Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
+
+select: true
+
+description:
+  This binding indicates that Xen grant mappings scheme needs to be enabled
+  for that device and specifies the ID of Xen domain where the corresponding
+  device (backend) resides. This is needed for the option to restrict memory
+  access using Xen grant mappings to work.
+
+properties:
+  xen,dev-domid:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      The domid (domain ID) of the domain where the device (backend) is running.
+
+additionalProperties: true
+
+examples:
+  - |
+    virtio_block@3000 {
+            compatible = "virtio,mmio";
+            reg = <0x3000 0x100>;
+            interrupts = <41>;
+
+            /* The device is located in Xen domain with ID 1 */
+            xen,dev-domid = <1>;
+    };
-- 
2.7.4