| 1 | Representing flash partitions in devicetree |
| 2 | |
| 3 | Partitions can be represented by sub-nodes of an mtd device. This can be used |
| 4 | on platforms which have strong conventions about which portions of a flash are |
| 5 | used for what purposes, but which don't use an on-flash partition table such |
| 6 | as RedBoot. |
| 7 | |
| 8 | #address-cells & #size-cells must both be present in the mtd device. There are |
| 9 | two valid values for both: |
| 10 | <1>: for partitions that require a single 32-bit cell to represent their |
| 11 | size/address (aka the value is below 4 GiB) |
| 12 | <2>: for partitions that require two 32-bit cells to represent their |
| 13 | size/address (aka the value is 4 GiB or greater). |
| 14 | |
| 15 | Required properties: |
| 16 | - reg : The partition's offset and size within the mtd bank. |
| 17 | |
| 18 | Optional properties: |
| 19 | - label : The label / name for this partition. If omitted, the label is taken |
| 20 | from the node name (excluding the unit address). |
| 21 | - read-only : This parameter, if present, is a hint to Linux that this |
| 22 | partition should only be mounted read-only. This is usually used for flash |
| 23 | partitions containing early-boot firmware images or data which should not be |
| 24 | clobbered. |
| 25 | |
| 26 | Examples: |
| 27 | |
| 28 | |
| 29 | flash@0 { |
| 30 | #address-cells = <1>; |
| 31 | #size-cells = <1>; |
| 32 | |
| 33 | partition@0 { |
| 34 | label = "u-boot"; |
| 35 | reg = <0x0000000 0x100000>; |
| 36 | read-only; |
| 37 | }; |
| 38 | |
| 39 | uimage@100000 { |
| 40 | reg = <0x0100000 0x200000>; |
| 41 | }; |
| 42 | }; |
| 43 | |
| 44 | flash@1 { |
| 45 | #address-cells = <1>; |
| 46 | #size-cells = <2>; |
| 47 | |
| 48 | /* a 4 GiB partition */ |
| 49 | partition@0 { |
| 50 | label = "filesystem"; |
| 51 | reg = <0x00000000 0x1 0x00000000>; |
| 52 | }; |
| 53 | }; |
| 54 | |
| 55 | flash@2 { |
| 56 | #address-cells = <2>; |
| 57 | #size-cells = <2>; |
| 58 | |
| 59 | /* an 8 GiB partition */ |
| 60 | partition@0 { |
| 61 | label = "filesystem #1"; |
| 62 | reg = <0x0 0x00000000 0x2 0x00000000>; |
| 63 | }; |
| 64 | |
| 65 | /* a 4 GiB partition */ |
| 66 | partition@200000000 { |
| 67 | label = "filesystem #2"; |
| 68 | reg = <0x2 0x00000000 0x1 0x00000000>; |
| 69 | }; |
| 70 | }; |