xref: /freebsd/sys/contrib/device-tree/Bindings/mtd/partition.txt (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1Flash partitions in device tree
2===============================
3
4Flash devices can be partitioned into one or more functional ranges (e.g. "boot
5code", "nvram", "kernel").
6
7Different devices may be partitioned in a different ways. Some may use a fixed
8flash layout set at production time. Some may use on-flash table that describes
9the geometry and naming/purpose of each functional region. It is also possible
10to see these methods mixed.
11
12To assist system software in locating partitions, we allow describing which
13method is used for a given flash device. To describe the method there should be
14a subnode of the flash device that is named 'partitions'. It must have a
15'compatible' property, which is used to identify the method to use.
16
17When a single partition is represented with a DT node (it depends on a used
18format) it may also be described using above rules ('compatible' and optionally
19some extra properties / subnodes). It allows describing more complex,
20hierarchical (multi-level) layouts and should be used if there is some
21significant relation between partitions or some partition internally uses
22another partitioning method.
23
24Available bindings are listed in the "partitions" subdirectory.
25
26
27Deprecated: partitions defined in flash node
28============================================
29
30For backwards compatibility partitions as direct subnodes of the flash device are
31supported. This use is discouraged.
32NOTE: also for backwards compatibility, direct subnodes that have a compatible
33string are not considered partitions, as they may be used for other bindings.
34