dts/bindings/fs/zephyr,fstab,littlefs.yaml

# Copyright (C) 2020 Nordic Semiconductor ASA
# SPDX-License-Identifier: Apache-2.0

description: |
    Description of pre-defined file systems.

compatible: "zephyr,fstab,littlefs"

include: "zephyr,fstab-common.yaml"

properties:
  # num-files and num-dirs are not filesystem-specific.

  read-size:
    type: int
    required: true
    description: |
      The size of file system read operations, in bytes.

      All read operations will be a multiple of this value.  A
      reasonable default is 16.

      This corresponds to CONFIG_FS_LITTLEFS_READ_SIZE.

  prog-size:
    type: int
    required: true
    description: |
      The size of file system program (write) operations, in bytes.

      All program operations will be a multiple of this value.  A
      reasonable default is 16.

      This corresponds to CONFIG_FS_LITTLEFS_PROG_SIZE.

  cache-size:
    type: int
    required: true
    description: |
      The size of block caches, in bytes.

      Each cache buffers a portion of a block in RAM.  The littlefs
      needs a read cache, a program cache, and one additional cache per
      file. Larger caches can improve performance by storing more data
      and reducing the number of disk accesses. Must be a multiple of
      the read and program sizes of the underlying flash device, and a
      factor of the block size.

      A reasonable default is 64.

      This corresponds to CONFIG_FS_LITTLEFS_CACHE_SIZE.

  lookahead-size:
    type: int
    required: true
    description: |
      The size of the lookahead buffer, in bytes.

      A larger lookahead buffer increases the number of blocks found
      during an allocation pass. The lookahead buffer is stored as a
      compact bitmap, so each byte of RAM can track 8 blocks. Must be a
      multiple of 8.

      A reasonable default is 32.

      This corresponds to CONFIG_FS_LITTLEFS_LOOKAHEAD_SIZE.

  block-cycles:
    type: int
    required: true
    description: |
      The number of erase cycles before moving data to another block.

      For dynamic wear leveling, the number of erase cycles before data
      is moved to another block.  Set to a non-positive value to disable
      leveling.

      This corresponds to CONFIG_FS_LITTLEFS_LOOKAHEAD_SIZE.