[PATCH v5 1/2] dt-bindings: reserved-memory: Introduce carved-out memory region binding

Maxime Ripard
2025-06-17T12:25:53Z

Some parts of the memory can be dedicated to specific purposes and
exposed as a dedicated memory allocator.

This is especially useful if that particular region has a particular
properties the rest of the memory doesn't have. For example, some
platforms have their entire RAM covered by ECC but for a small area
meant to be used by applications that don't need ECC, and its associated
overhead.

Let's introduce a binding to describe such a region and allow the OS to
create a dedicated memory allocator for it.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
.../bindings/reserved-memory/carved-out.yaml | 49 ++++++++++++++++++++++
1 file changed, 49 insertions(+)

diff --git a/Documentation/devicetree/bindings/reserved-memory/carved-out.yaml b/Documentation/devicetree/bindings/reserved-memory/carved-out.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..9ab5d1ebd9ebd9111b7c064fabe1c45e752da83b
--- /dev/null
+++ b/Documentation/devicetree/bindings/reserved-memory/carved-out.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/reserved-memory/carved-out.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Carved-out Memory Region
+
+description: |
+ Specifies that the reserved memory region has been carved out of the
+ main memory allocator, and is intended to be used by the OS as a
+ dedicated memory allocator.
+
+maintainers:
+ - Maxime Ripard <mripard@kernel.org>
+
+properties:
+ compatible:
+ const: carved-out
+
+ reg:
+ description: region of memory that is carved out.
+
+allOf:
+ - $ref: reserved-memory.yaml
+ - not:
+ required:
+ - reusable
+ - not:
+ required:
+ - no-map
+
+required:
+ - compatible
+ - reg
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ reserved-memory {
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ memory@12340000 {
+ compatible = "carved-out";
+ reg = <0x12340000 0x00800000>;
+ };
+ };

--
2.49.0