xref: /freebsd/sys/contrib/device-tree/Bindings/nvmem/u-boot,env.yaml (revision 84943d6f38e936ac3b7a3947ca26eeb27a39f938) 
1# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/nvmem/u-boot,env.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: U-Boot environment variables
8
9description: |
10  U-Boot uses environment variables to store device parameters and
11  configuration. They may be used for booting process, setup or keeping end user
12  info.
13
14  Data is stored using U-Boot specific formats (variant specific header and NUL
15  separated key-value pairs).
16
17  Environment data can be stored on various storage entities, e.g.:
18  1. Raw flash partition
19  2. UBI volume
20
21  This binding allows marking storage device (as containing env data) and
22  specifying used format.
23
24  Right now only flash partition case is covered but it may be extended to e.g.
25  UBI volumes in the future.
26
27  Variables can be defined as NVMEM device subnodes.
28
29maintainers:
30  - Rafał Miłecki <rafal@milecki.pl>
31
32properties:
33  compatible:
34    oneOf:
35      - description: A standalone env data block
36        const: u-boot,env
37      - description: Two redundant blocks with active one flagged
38        const: u-boot,env-redundant-bool
39      - description: Two redundant blocks with active having higher counter
40        const: u-boot,env-redundant-count
41      - description: Broadcom's variant with custom header
42        const: brcm,env
43
44  reg:
45    maxItems: 1
46
47  bootcmd:
48    type: object
49    description: Command to use for automatic booting
50
51  ethaddr:
52    type: object
53    description: Ethernet interfaces base MAC address.
54    additionalProperties: false
55
56    properties:
57      "#nvmem-cell-cells":
58        description: The first argument is a MAC address offset.
59        const: 1
60
61additionalProperties: false
62
63examples:
64  - |
65    partitions {
66        compatible = "fixed-partitions";
67        #address-cells = <1>;
68        #size-cells = <1>;
69
70        partition@0 {
71            reg = <0x0 0x40000>;
72            label = "u-boot";
73            read-only;
74        };
75
76        env: partition@40000 {
77            compatible = "u-boot,env";
78            reg = <0x40000 0x10000>;
79
80            mac: ethaddr {
81                #nvmem-cell-cells = <1>;
82            };
83        };
84    };
85  - |
86    partitions {
87        compatible = "fixed-partitions";
88        #address-cells = <1>;
89        #size-cells = <1>;
90
91        partition@0 {
92            reg = <0x0 0x100000>;
93            compatible = "brcm,u-boot";
94            label = "u-boot";
95
96            partition-u-boot-env {
97                compatible = "brcm,env";
98
99                ethaddr {
100                };
101            };
102        };
103    };
104