On 2.03.2022 22:59, Rob Herring wrote:
On Thu, Feb 17, 2022 at 11:24:48AM +0100, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@xxxxxxxxxx>
UBI is often used on embedded devices to store UBI volumes with device
configuration / calibration data. Such volumes may need to be documented
and referenced for proper boot & setup.
Some examples:
1. U-Boot environment variables
2. Device calibration data
3. Default setup (e.g. initial password)
Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
.../bindings/mtd/partitions/ubi.yaml | 67 +++++++++++++++++++
1 file changed, 67 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mtd/partitions/ubi.yaml
diff --git a/Documentation/devicetree/bindings/mtd/partitions/ubi.yaml b/Documentation/devicetree/bindings/mtd/partitions/ubi.yaml
new file mode 100644
index 000000000000..cd081f06d4cb
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/partitions/ubi.yaml
@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/partitions/ubi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: UBI (Unsorted Block Images) device
+
+description: |
+ UBI is a layer providing logical volumes (consisting of logical blocks) on top
+ of raw flash devices. It deals with low-level flash issues (bit-flips, bad
+ physical eraseblocks, wearing) providing a reliable data storage.
+
+ UBI device is built and stored in a single flash partition.
+
+ Some (usually embedded) devices use UBI volumes of specific names or indexes
+ to store setup / configuration data. This binding allows describing such
+ volumes so they can be identified and referenced by consumers.
+
+maintainers:
+ - Rafał Miłecki <rafal@xxxxxxxxxx>
+
+allOf:
+ - $ref: partition.yaml#
+
+properties:
+ compatible:
+ const: ubi
+
+patternProperties:
+ "^volume-[0-9a-f]+$":
+ type: object
+ description: UBI volume
+ properties:
+ volume-name:
+ $ref: /schemas/types.yaml#/definitions/string
+ volume-id:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ anyOf:
+ - required:
+ - volume-name
+ - required:
+ - volume-id
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ partitions {
+ compatible = "fixed-partitions";
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ partition@0 {
+ compatible = "ubi";
+ reg = <0x0000000 0x1000000>;
+ label = "filesystem";
+
+ env: volume-0 {
+ volume-name = "u-boot-env";
Why not do 'compatible = "u-boot,env";' to align with normal partitions?
I mean to reserve "compatible" for describing UBI volume content.
If I manage to get
[PATCH V3] dt-bindings: nvmem: add U-Boot environment variables binding
https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20220228131250.16943-1-zajec5@xxxxxxxxx/
accepted, it'll allow me to later work on something like:
env: volume-0 {
compatible = "u-boot,env";
volume-name = "u-boot-env";
};
(I believe) I'll need (in the final shape) two properties:
1. One for describing UBI volume ("compatible")
2. One for identifying UBI volume ("volume-name" / "volume-id")
It's similar design to the "compatible" vs. "reg" in IO hw blocks.
Or 'label'?
I could replace "volume-name" with "label" but someone once told me that:
> 'label' is supposed to correspond to a sticker on a port or something
> human identifiable
;) https://patchwork.ozlabs.org/comment/2812214/
So I don't want to abuse "label" here.
We have enough ways to identify things, I don't think we need another.
+ };
+
+ calibration: volume-1 {
Are 0 and 1 meaningful or just made up indexing?
Made up indexing. I need unique nodenames but @[0-9a-f] doesn't appply here.
+ volume-id = <99>;
+ };
+ };
+ };
--
2.34.1
