fixed-partitions

Note

An implementation of a driver matching this compatible is available in subsys/storage/flash_map/flash_map_default.c.

Description

This binding is used to describe fixed partitions of a flash (or
other nonvolatile storage) memory.

Here is an example:

  &flash0 {
          partitions {
                  compatible = "fixed-partitions";
                  #address-cells = <1>;
                  #size-cells = <1>;

                  boot_partition: partition@0 {
                          label = "mcuboot";
                          reg = <0x00000000 0x0000C000>;
                  };
                  slot0_partition: partition@c000 {
                          label = "image-0";
                          reg = <0x0000C000 0x00076000>;
                  };
                  slot1_partition: partition@82000 {
                          label = "image-1";
                          reg = <0x00082000 0x00076000>;
                  };

                  /*
                   * The flash starting at 0x000f8000 and ending at
                   * 0x000fffff is reserved for use by the application.
                   */

                  /*
                   * Storage partition will be used by FCB/LittleFS/NVS
                   * if enabled.
                   */
                  storage_partition: partition@f8000 {
                          label = "storage";
                          reg = <0x000f8000 0x00008000>;
                  };
          };
  };

Note that the usual name for this node is 'partitions'.
The fixed-partitions node should be a child of the flash
memory node. Note also that the flash memory node is usually
different from the node representing the flash controller
IP block.

Above, slot0_partition's register address 0xc000 means that
the partition begins at that offset from the parent flash
memory flash0's base address. That is, partition addresses
are relative; physical addresses must be calculated by adding
the start address of flash0 in memory to each partition's
reg address.

Properties

Top level properties

These property descriptions apply to “fixed-partitions” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

(None)

Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “fixed-partitions” compatible.

Name

Type

Details

#address-cells

int

Number of cells required to represent a child node's
reg property address. This must be large enough to
represent the start offset of each partition.

#size-cells

int

Number of cells required to represent a child node's
reg property address. This must be large enough to
represent the size of each partition in bytes.

Child node properties

Name

Type

Details

label

string

Human readable string describing the flash partition.

See Important properties for more information.

read-only

boolean

set this property if the partition is read-only

reg

array

This should be in the format <OFFSET SIZE>, where OFFSET
is the offset of the flash partition relative to the base
address of the parent memory, and SIZE is the size of
the partition in bytes.

This property is required.

See Important properties for more information.