On Thu, Mar 3, 2022 at 2:32 AM Rafał Miłecki zajec5@gmail.com wrote:
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@milecki.pl
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:
- U-Boot environment variables
- Device calibration data
- Default setup (e.g. initial password)
Signed-off-by: Rafał Miłecki rafal@milecki.pl
.../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@milecki.pl
+allOf:
- $ref: partition.yaml#
+properties:
- compatible:
- const: ubi
+patternProperties:
- "^volume-[0-9a-f]+$":
- type: object
- description: UBI volume
- properties:
volume-name:$ref: /schemas/types.yaml#/definitions/stringvolume-id:$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/2022022813125... 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:
- One for describing UBI volume ("compatible")
- One for identifying UBI volume ("volume-name" / "volume-id")
It's similar design to the "compatible" vs. "reg" in IO hw blocks.
That's what it is vs. what instance. You need a better example if that's what you are trying to show. I guess if you were doing A/B updates you'd have something like 'volume-name = "u-boot-env-b"'?
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
Yes, it could be a human wanting to identify it. The question is whether s/w does too.
The other aspect is there's also filesystem/partition label's. Those are generally set by humans and opaque to the s/w. If the use is aligned with how those labels are used, then I'd be okay with the DT 'label' here.
;) 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.
Maybe use "volume-$volumename" or "volume-$volumeid" instead?
Rob