1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/mtd/partitions/partition.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Partition
8
9 description: |
10 This binding describes a single flash partition. Each partition must have its
11 relative offset and size specified. Depending on partition function extra
12 properties can be used.
13
14 A partition may be dynamically allocated by a specific parser at runtime.
15 In this specific case, a specific suffix is required to the node name.
16 Everything after 'partition-' will be used as the partition name to compare
17 with the one dynamically allocated by the specific parser.
18 If the partition contains invalid char a label can be provided that will
19 be used instead of the node name to make the comparison.
20 This is used to assign an OF node to the dynamiccally allocated partition
21 so that subsystem like NVMEM can provide an OF node and declare NVMEM cells.
22 The OF node will be assigned only if the partition label declared match the
23 one assigned by the parser at runtime.
24
25 maintainers:
26 - Rafał Miłecki <rafal@milecki.pl>
27
28 properties:
29 reg:
30 description: partition's offset and size within the flash
31 maxItems: 1
32
33 label:
34 description: The label / name for this partition. If omitted, the label
35 is taken from the node name (excluding the unit address).
36
37 read-only:
38 description: This parameter, if present, is a hint that this partition
39 should only be mounted read-only. This is usually used for flash
40 partitions containing early-boot firmware images or data which should
41 not be clobbered.
42 type: boolean
43
44 lock:
45 description: Do not unlock the partition at initialization time (not
46 supported on all devices)
47 type: boolean
48
49 slc-mode:
50 description: This parameter, if present, allows one to emulate SLC mode
51 on a partition attached to an MLC NAND thus making this partition
52 immune to paired-pages corruptions
53 type: boolean
54
55 linux,rootfs:
56 description: Marks partition that contains root filesystem to mount and boot
57 user space from
58 type: boolean
59
60 align:
61 $ref: /schemas/types.yaml#/definitions/uint32
62 minimum: 2
63 maximum: 0x80000000
64 multipleOf: 2
65 description:
66 This sets the alignment of the entry in bytes.
67
68 The entry offset is adjusted so that the entry starts on an aligned
69 boundary within the containing section or image. For example ‘align =
70 <16>’ means that the entry will start on a 16-byte boundary. This may
71 mean that padding is added before the entry. The padding is part of
72 the containing section but is not included in the entry, meaning that
73 an empty space may be created before the entry starts. Alignment
74 must be a power of 2. If ‘align’ is not provided, no alignment is
75 performed.
76
77 align-size:
78 $ref: /schemas/types.yaml#/definitions/uint32
79 minimum: 2
80 maximum: 0x80000000
81 multipleOf: 2
82 description:
83 This sets the alignment of the entry size in bytes. It must be a power
84 of 2.
85
86 For example, to ensure that the size of an entry is a multiple of 64
87 bytes, set this to 64. While this does not affect the content of the
88 entry itself (the padding is performed only when its parent section is
89 assembled), the end result is that the entry ends with the padding
90 bytes, so may grow. If ‘align-size’ is not provided, no alignment is
91 performed.
92
93 align-end:
94 $ref: /schemas/types.yaml#/definitions/uint32
95 minimum: 2
96 maximum: 0x80000000
97 multipleOf: 2
98 description:
99 This sets the alignment (in bytes) of the end of an entry with respect
100 to the containing section. It must be a power of 2.
101
102 Some entries require that they end on an alignment boundary,
103 regardless of where they start. This does not move the start of the
104 entry, so the content of the entry will still start at the beginning.
105 But there may be padding at the end. While this does not affect the
106 content of the entry itself (the padding is performed only when its
107 parent section is assembled), the end result is that the entry ends
108 with the padding bytes, so may grow. If ‘align-end’ is not provided,
109 no alignment is performed.
110
111 if:
112 not:
113 required: [ reg ]
114 then:
115 properties:
116 $nodename:
117 pattern: '^partition-.*$'
118
119 # This is a generic file other binding inherit from and extend
120 additionalProperties: true
121
122 examples:
123 - |
124 partitions {
125 compatible = "fixed-partitions";
126 #address-cells = <1>;
127 #size-cells = <1>;
128
129 partition@100000 {
130 compatible = "u-boot";
131 reg = <0x100000 0xf00000>;
132 align-size = <0x1000>;
133 align-end = <0x10000>;
134 };
135
136 partition@200000 {
137 compatible = "tfa-bl31";
138 reg = <0x200000 0x100000>;
139 align = <0x4000>;
140 };
141 };
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