projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 83619ea0 JL |
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. | |
| e79265ba | 7 | NOTE: if the sub-node has a compatible string, then it is not a partition. |
| 83619ea0 | 8 | |
| 05ff8c25 JS |
9 | #address-cells & #size-cells must both be present in the mtd device. There are |
| 10 | two valid values for both: | |
| 11 | <1>: for partitions that require a single 32-bit cell to represent their | |
| 12 | size/address (aka the value is below 4 GiB) | |
| 13 | <2>: for partitions that require two 32-bit cells to represent their | |
| 14 | size/address (aka the value is 4 GiB or greater). | |
| 83619ea0 JL |
15 | |
| 16 | Required properties: | |
| 17 | - reg : The partition's offset and size within the mtd bank. | |
| 18 | ||
| 19 | Optional properties: | |
| 20 | - label : The label / name for this partition. If omitted, the label is taken | |
| 21 | from the node name (excluding the unit address). | |
| 22 | - read-only : This parameter, if present, is a hint to Linux that this | |
| 23 | partition should only be mounted read-only. This is usually used for flash | |
| 24 | partitions containing early-boot firmware images or data which should not be | |
| 25 | clobbered. | |
| 26 | ||
| 27 | Examples: | |
| 28 | ||
| 29 | ||
| 30 | flash@0 { | |
| 31 | #address-cells = <1>; | |
| 32 | #size-cells = <1>; | |
| 33 | ||
| 34 | partition@0 { | |
| 35 | label = "u-boot"; | |
| 36 | reg = <0x0000000 0x100000>; | |
| 37 | read-only; | |
| 38 | }; | |
| 39 | ||
| 40 | uimage@100000 { | |
| 41 | reg = <0x0100000 0x200000>; | |
| 42 | }; | |
| bf6c9734 | 43 | }; |
| 05ff8c25 JS |
44 | |
| 45 | flash@1 { | |
| 46 | #address-cells = <1>; | |
| 47 | #size-cells = <2>; | |
| 48 | ||
| 49 | /* a 4 GiB partition */ | |
| 50 | partition@0 { | |
| 51 | label = "filesystem"; | |
| 52 | reg = <0x00000000 0x1 0x00000000>; | |
| 53 | }; | |
| 54 | }; | |
| 55 | ||
| 56 | flash@2 { | |
| 57 | #address-cells = <2>; | |
| 58 | #size-cells = <2>; | |
| 59 | ||
| 60 | /* an 8 GiB partition */ | |
| 61 | partition@0 { | |
| 62 | label = "filesystem #1"; | |
| 63 | reg = <0x0 0x00000000 0x2 0x00000000>; | |
| 64 | }; | |
| 65 | ||
| 66 | /* a 4 GiB partition */ | |
| 67 | partition@200000000 { | |
| 68 | label = "filesystem #2"; | |
| 69 | reg = <0x2 0x00000000 0x1 0x00000000>; | |
| 70 | }; | |
| 71 | }; |