Commit 5db1c2db authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Rob Herring
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dt-bindings: nvmem: add U-Boot environment variables binding 



U-Boot uses environment variables for storing device setup data. It
usually needs to be accessed by a bootloader, kernel and often
user-space.

This binding allows describing environment data located in a raw flash
partition. It's treated as NVMEM device and can be reused later for
other storage devices.

Using DT should be cleaner than hardcoding & duplicating such info in
multiple places. Bootloader & kernel can share DTS and user-space can
try reading it too or just have correct data exposed by a kernel.

A custom "compatible" string allows system to automatically load
relevant NVMEM driver but phandle can be also used for reading raw
location.

Signed-off-by: default avatarRafał Miłecki <rafal@milecki.pl>
Reviewed-by: default avatarTom Rini <trini@konsulko.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220228131250.16943-1-zajec5@gmail.com
parent 3d8fa7a2

Documentation/devicetree/bindings/nvmem/u-boot,env.yaml

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# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause

%YAML 1.2

---

$id: http://devicetree.org/schemas/nvmem/u-boot,env.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: U-Boot environment variables



description: |

  U-Boot uses environment variables to store device parameters and

  configuration. They may be used for booting process, setup or keeping end user

  info.



  Data is stored using U-Boot specific formats (variant specific header and NUL

  separated key-value pairs).



  Environment data can be stored on various storage entities, e.g.:

  1. Raw flash partition

  2. UBI volume



  This binding allows marking storage device (as containing env data) and

  specifying used format.



  Right now only flash partition case is covered but it may be extended to e.g.

  UBI volumes in the future.



maintainers:

  - Rafał Miłecki <rafal@milecki.pl>



properties:

  compatible:

    oneOf:

      - description: A standalone env data block

        const: u-boot,env

      - description: Two redundant blocks with active one flagged

        const: u-boot,env-redundant-bool

      - description: Two redundant blocks with active having higher counter

        const: u-boot,env-redundant-count



  reg:

    maxItems: 1



additionalProperties: false



examples:

  - |

    partitions {

        compatible = "fixed-partitions";

        #address-cells = <1>;

        #size-cells = <1>;



        partition@0 {

            reg = <0x0 0x40000>;

            label = "u-boot";

            read-only;

        };



        env: partition@40000 {

            compatible = "u-boot,env";

            reg = <0x40000 0x10000>;

        };

    };

MAINTAINERS

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@@ -19665,6 +19665,11 @@ W: http://linuxtv.org 
T:	git git://linuxtv.org/media_tree.git

F:	drivers/media/pci/tw686x/









U-BOOT ENVIRONMENT VARIABLES









M:	Rafał Miłecki <rafal@milecki.pl>









S:	Maintained









F:	Documentation/devicetree/bindings/nvmem/u-boot,env.yaml

















UACCE ACCELERATOR FRAMEWORK









M:	Zhangfei Gao <zhangfei.gao@linaro.org>









M:	Zhou Wang <wangzhou1@hisilicon.com>