1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/nvmem/layouts/u-boot,env.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: U-Boot environment variables layout
8
9 description: |
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 Variables can be defined as NVMEM device subnodes.
25
26 maintainers:
27 - Rafał Miłecki <rafal@milecki.pl>
28
29 properties:
30 compatible:
31 oneOf:
32 - description: A standalone env data block
33 const: u-boot,env
34 - description: Two redundant blocks with active one flagged
35 const: u-boot,env-redundant-bool
36 - description: Two redundant blocks with active having higher counter
37 const: u-boot,env-redundant-count
38 - description: Broadcom's variant with custom header
39 const: brcm,env
40
41 reg:
42 description: Partition offset and size for env on top of MTD
43 maxItems: 1
44
45 bootcmd:
46 type: object
47 description: Command to use for automatic booting
48
49 ethaddr:
50 type: object
51 description: Ethernet interfaces base MAC address.
52 additionalProperties: false
53
54 properties:
55 "#nvmem-cell-cells":
56 description: The first argument is a MAC address offset.
57 const: 1
58
59 allOf:
60 - if:
61 properties:
62 $nodename:
63 not:
64 contains:
65 pattern: "^partition@[0-9a-f]+$"
66 then:
67 properties:
68 reg: false
69
70 additionalProperties: false
71
72 examples:
73 - |
74 partitions {
75 compatible = "fixed-partitions";
76 #address-cells = <1>;
77 #size-cells = <1>;
78
79 partition@0 {
80 reg = <0x0 0x40000>;
81 label = "u-boot";
82 read-only;
83 };
84
85 env: partition@40000 {
86 compatible = "u-boot,env";
87 reg = <0x40000 0x10000>;
88
89 mac: ethaddr {
90 #nvmem-cell-cells = <1>;
91 };
92 };
93 };
94 - |
95 partitions {
96 compatible = "fixed-partitions";
97 #address-cells = <1>;
98 #size-cells = <1>;
99
100 partition@0 {
101 reg = <0x0 0x100000>;
102 compatible = "brcm,u-boot";
103 label = "u-boot";
104
105 partition-u-boot-env {
106 compatible = "brcm,env";
107
108 ethaddr {
109 };
110 };
111 };
112 };
113 - |
114 partition@0 {
115 reg = <0x0 0x100000>;
116 label = "ubi";
117 compatible = "linux,ubi";
118
119 volumes {
120 ubi-volume-u-boot-env {
121 volname = "env";
122
123 nvmem-layout {
124 compatible = "u-boot,env";
125
126 ethaddr {
127 #nvmem-cell-cells = <1>;
128 };
129 };
130 };
131 };
132 };
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