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1Representing flash partitions in devicetree
2
3Partitions can be represented by sub-nodes of an mtd device. This can be used
4on platforms which have strong conventions about which portions of a flash are
5used for what purposes, but which don't use an on-flash partition table such
6as RedBoot.
7
8The partition table should be a subnode of the mtd node and should be named
9'partitions'. This node should have the following property:
10- compatible : (required) must be "fixed-partitions"
11Partitions are then defined in subnodes of the partitions node.
12
13For backwards compatibility partitions as direct subnodes of the mtd device are
14supported. This use is discouraged.
15NOTE: also for backwards compatibility, direct subnodes that have a compatible
16string are not considered partitions, as they may be used for other bindings.
17
18#address-cells & #size-cells must both be present in the partitions subnode of the
19mtd device. There are two valid values for both:
20<1>: for partitions that require a single 32-bit cell to represent their
21     size/address (aka the value is below 4 GiB)
22<2>: for partitions that require two 32-bit cells to represent their
23     size/address (aka the value is 4 GiB or greater).
24
25Required properties:
26- reg : The partition's offset and size within the mtd bank.
27
28Optional properties:
29- label : The label / name for this partition.  If omitted, the label is taken
30  from the node name (excluding the unit address).
31- read-only : This parameter, if present, is a hint to Linux that this
32  partition should only be mounted read-only. This is usually used for flash
33  partitions containing early-boot firmware images or data which should not be
34  clobbered.
35- lock : Do not unlock the partition at initialization time (not supported on
36  all devices)
37
38Examples:
39
40
41flash@0 {
42	partitions {
43		compatible = "fixed-partitions";
44		#address-cells = <1>;
45		#size-cells = <1>;
46
47		partition@0 {
48			label = "u-boot";
49			reg = <0x0000000 0x100000>;
50			read-only;
51		};
52
53		uimage@100000 {
54			reg = <0x0100000 0x200000>;
55		};
56	};
57};
58
59flash@1 {
60	partitions {
61		compatible = "fixed-partitions";
62		#address-cells = <1>;
63		#size-cells = <2>;
64
65		/* a 4 GiB partition */
66		partition@0 {
67			label = "filesystem";
68			reg = <0x00000000 0x1 0x00000000>;
69		};
70	};
71};
72
73flash@2 {
74	partitions {
75		compatible = "fixed-partitions";
76		#address-cells = <2>;
77		#size-cells = <2>;
78
79		/* an 8 GiB partition */
80		partition@0 {
81			label = "filesystem #1";
82			reg = <0x0 0x00000000 0x2 0x00000000>;
83		};
84
85		/* a 4 GiB partition */
86		partition@200000000 {
87			label = "filesystem #2";
88			reg = <0x2 0x00000000 0x1 0x00000000>;
89		};
90	};
91};
92