Merge branch 'feature/enable-fat16' into 'master'

Enable FAT16 for FATFS generator

Closes IDF-4046

See merge request espressif/esp-idf!16283

components/fatfs/Kconfig

@@ -7,6 +7,46 @@ menu "FAT Filesystem support"
         help
             Number of volumes (logical drives) to use.
 
+    choice FATFS_SECTOR_SIZE
+        prompt "Sector size"
+        default FATFS_SECTOR_4096
+        help
+            Specify the size of the sector in bytes for FATFS partition generator.
+
+        config FATFS_SECTOR_512
+            bool "512"
+        config FATFS_SECTOR_1024
+            bool "1024"
+        config FATFS_SECTOR_2048
+            bool "2048"
+        config FATFS_SECTOR_4096
+            bool "4096"
+    endchoice
+
+    choice FATFS_SECTORS_PER_CLUSTER
+        prompt "Sectors per cluster"
+        default FATFS_SECTORS_PER_CLUSTER_1
+        help
+            This value specifies how many sectors there are in one cluster.
+
+        config FATFS_SECTORS_PER_CLUSTER_1
+            bool "1"
+        config FATFS_SECTORS_PER_CLUSTER_2
+            bool "2"
+        config FATFS_SECTORS_PER_CLUSTER_4
+            bool "4"
+        config FATFS_SECTORS_PER_CLUSTER_8
+            bool "8"
+        config FATFS_SECTORS_PER_CLUSTER_16
+            bool "16"
+        config FATFS_SECTORS_PER_CLUSTER_32
+            bool "32"
+        config FATFS_SECTORS_PER_CLUSTER_64
+            bool "64"
+        config FATFS_SECTORS_PER_CLUSTER_128
+            bool "128"
+    endchoice
+
     choice FATFS_CHOOSE_CODEPAGE
         prompt "OEM Code Page"
         default FATFS_CODEPAGE_437
@@ -64,6 +104,21 @@ menu "FAT Filesystem support"
 
     endchoice
 
+    choice FATFS_CHOOSE_TYPE
+        prompt "FAT type"
+        default FATFS_AUTO_TYPE
+        help
+            If user specifies automatic detection of the FAT type,
+            the FATFS generator will determine the type by the size.
+
+        config FATFS_AUTO_TYPE
+            bool "Select a suitable FATFS type automatically."
+        config FATFS_FAT12
+            bool "FAT12"
+        config FATFS_FAT16
+            bool "FAT16"
+    endchoice
+
     config FATFS_CODEPAGE
         int
         default 0 if FATFS_CODEPAGE_DYNAMIC
@@ -96,7 +151,7 @@ menu "FAT Filesystem support"
         help
             Support long filenames in FAT. Long filename data increases
             memory usage. FATFS can be configured to store the buffer for
-            long filename data in stack or heap.
+            long filename data in stack or heap (Currently not supported by FATFS partition generator).
 
         config FATFS_LFN_NONE
             bool "No long filenames"

components/fatfs/fatfsgen.py

@@ -5,11 +5,12 @@
 import os
 from typing import Any, List, Optional
 
-from construct import Const, Int8ul, Int16ul, Int32ul, PaddedString, Struct
 from fatfsgen_utils.fat import FAT
+from fatfsgen_utils.fatfs_parser import FATFSParser
 from fatfsgen_utils.fatfs_state import FATFSState
 from fatfsgen_utils.fs_object import Directory
-from fatfsgen_utils.utils import generate_4bytes_random, get_args_for_partition_generator, pad_string
+from fatfsgen_utils.utils import (BYTES_PER_DIRECTORY_ENTRY, FAT32, generate_4bytes_random,
+                                  get_args_for_partition_generator, pad_string, read_filesystem)
 
 
 class FATFS:
@@ -17,35 +18,6 @@ class FATFS:
     The class FATFS provides API for generating FAT file system.
     It contains reference to the FAT table and to the root directory.
     """
-    MAX_VOL_LAB_SIZE = 11
-    MAX_OEM_NAME_SIZE = 8
-    MAX_FS_TYPE_SIZE = 8
-    BOOT_HEADER_SIZE = 512
-
-    BOOT_SECTOR_HEADER = Struct(
-        'BS_jmpBoot' / Const(b'\xeb\xfe\x90'),
-        'BS_OEMName' / PaddedString(MAX_OEM_NAME_SIZE, 'utf-8'),
-        'BPB_BytsPerSec' / Int16ul,
-        'BPB_SecPerClus' / Int8ul,
-        'BPB_RsvdSecCnt' / Int16ul,
-        'BPB_NumFATs' / Int8ul,
-        'BPB_RootEntCnt' / Int16ul,
-        'BPB_TotSec16' / Int16ul,
-        'BPB_Media' / Int8ul,
-        'BPB_FATSz16' / Int16ul,
-        'BPB_SecPerTrk' / Int16ul,
-        'BPB_NumHeads' / Int16ul,
-        'BPB_HiddSec' / Int32ul,
-        'BPB_TotSec32' / Int32ul,
-        'BS_DrvNum' / Const(b'\x80'),
-        'BS_Reserved1' / Const(b'\x00'),
-        'BS_BootSig' / Const(b'\x29'),
-        'BS_VolID' / Int32ul,
-        'BS_VolLab' / PaddedString(MAX_VOL_LAB_SIZE, 'utf-8'),
-        'BS_FilSysType' / PaddedString(MAX_FS_TYPE_SIZE, 'utf-8'),
-        'BS_EMPTY' / Const(448 * b'\x00'),
-        'Signature_word' / Const(b'\x55\xAA')
-    )
 
     def __init__(self,
                  binary_image_path: Optional[str] = None,
@@ -55,7 +27,6 @@ class FATFS:
                  sectors_per_cluster: int = 1,
                  sector_size: int = 0x1000,
                  sectors_per_fat: int = 1,
-                 root_dir_sectors_cnt: int = 4,
                  hidden_sectors: int = 0,
                  long_names_enabled: bool = False,
                  entry_size: int = 32,
@@ -64,10 +35,18 @@ class FATFS:
                  sec_per_track: int = 0x3f,
                  volume_label: str = 'Espressif',
                  file_sys_type: str = 'FAT',
+                 root_entry_count: int = 512,
+                 explicit_fat_type: int = None,
                  media_type: int = 0xf8) -> None:
 
+        assert (root_entry_count * BYTES_PER_DIRECTORY_ENTRY) % sector_size == 0
+        assert ((root_entry_count * BYTES_PER_DIRECTORY_ENTRY) // sector_size) % 2 == 0
+
+        root_dir_sectors_cnt = (root_entry_count * BYTES_PER_DIRECTORY_ENTRY) // sector_size
+
         self.state = FATFSState(entry_size=entry_size,
                                 sector_size=sector_size,
+                                explicit_fat_type=explicit_fat_type,
                                 reserved_sectors_cnt=reserved_sectors_cnt,
                                 root_dir_sectors_cnt=root_dir_sectors_cnt,
                                 size=size,
@@ -83,13 +62,13 @@ class FATFS:
                                 volume_label=volume_label,
                                 oem_name=oem_name)
         binary_image = bytearray(
-            self.read_filesystem(binary_image_path) if binary_image_path else self.create_empty_fatfs())
+            read_filesystem(binary_image_path) if binary_image_path else self.create_empty_fatfs())
         self.state.binary_image = binary_image
 
         self.fat = FAT(fatfs_state=self.state,
                        reserved_sectors_cnt=self.state.reserved_sectors_cnt)
 
-        self.root_directory = Directory(name='A',  # the name is not important
+        self.root_directory = Directory(name='A',  # the name is not important, must be string
                                         size=self.state.root_dir_sectors_cnt * self.state.sector_size,
                                         fat=self.fat,
                                         cluster=self.fat.clusters[1],
@@ -105,6 +84,7 @@ class FATFS:
         parent_dir = self.root_directory
         if path_from_root:
             parent_dir = self.root_directory.recursive_search(path_from_root, self.root_directory)
+
         self.root_directory.new_directory(name=name, parent=parent_dir, path_from_root=path_from_root)
 
     def write_content(self, path_from_root: List[str], content: bytes) -> None:
@@ -117,36 +97,31 @@ class FATFS:
         sectors_count = self.state.size // self.state.sector_size
         volume_uuid = generate_4bytes_random()
         return (
-            FATFS.BOOT_SECTOR_HEADER.build(
+            FATFSParser.BOOT_SECTOR_HEADER.build(
-                dict(BS_OEMName=pad_string(self.state.oem_name, size=FATFS.MAX_OEM_NAME_SIZE),
+                dict(BS_OEMName=pad_string(self.state.oem_name, size=FATFSParser.MAX_OEM_NAME_SIZE),
-                     BPB_BytsPerSec=self.state.sectors_per_cluster * self.state.sector_size,
+                     BPB_BytsPerSec=self.state.sector_size,
                      BPB_SecPerClus=self.state.sectors_per_cluster,
                      BPB_RsvdSecCnt=self.state.reserved_sectors_cnt,
                      BPB_NumFATs=self.state.fat_tables_cnt,
                      BPB_RootEntCnt=self.state.entries_root_count,
-                     BPB_TotSec16=0x00 if self.state.fatfs_type == FATFSState.FAT32 else sectors_count,
+                     BPB_TotSec16=0x00 if self.state.fatfs_type == FAT32 else sectors_count,
                      BPB_Media=self.state.media_type,
                      BPB_FATSz16=self.state.sectors_per_fat_cnt,
                      BPB_SecPerTrk=self.state.sec_per_track,
                      BPB_NumHeads=self.state.num_heads,
                      BPB_HiddSec=self.state.hidden_sectors,
-                     BPB_TotSec32=sectors_count if self.state.fatfs_type == FATFSState.FAT32 else 0x00,
+                     BPB_TotSec32=sectors_count if self.state.fatfs_type == FAT32 else 0x00,
                      BS_VolID=volume_uuid,
-                     BS_VolLab=pad_string(self.state.volume_label, size=FATFS.MAX_VOL_LAB_SIZE),
+                     BS_VolLab=pad_string(self.state.volume_label, size=FATFSParser.MAX_VOL_LAB_SIZE),
-                     BS_FilSysType=pad_string(self.state.file_sys_type, size=FATFS.MAX_FS_TYPE_SIZE)
+                     BS_FilSysType=pad_string(self.state.file_sys_type, size=FATFSParser.MAX_FS_TYPE_SIZE)
                      )
             )
-            + (self.state.sector_size - FATFS.BOOT_HEADER_SIZE) * b'\x00'
+            + (self.state.sector_size - FATFSParser.BOOT_HEADER_SIZE) * b'\x00'
             + self.state.sectors_per_fat_cnt * self.state.fat_tables_cnt * self.state.sector_size * b'\x00'
             + self.state.root_dir_sectors_cnt * self.state.sector_size * b'\x00'
             + self.state.data_sectors * self.state.sector_size * b'\xff'
         )
 
-    @staticmethod
-    def read_filesystem(path: str) -> bytearray:
-        with open(path, 'rb') as fs_file:
-            return bytearray(fs_file.read())
-
     def write_filesystem(self, output_path: str) -> None:
         with open(output_path, 'wb') as output:
             output.write(bytearray(self.state.binary_image))
@@ -190,13 +165,17 @@ class FATFS:
         self._generate_partition_from_folder(folder_name, folder_path=path_to_folder, is_dir=True)
 
 
-if __name__ == '__main__':
+def main() -> None:
     args = get_args_for_partition_generator('Create a FAT filesystem and populate it with directory content')
-    input_dir = args.input_directory
+    fatfs = FATFS(sector_size=args.sector_size,
+                  sectors_per_cluster=args.sectors_per_cluster,
+                  size=args.partition_size,
+                  root_entry_count=args.root_entry_count,
+                  explicit_fat_type=args.fat_type)
 
-    partition_size = int(str(args.partition_size), 0)
+    fatfs.generate(args.input_directory)
-    sector_size_bytes = int(str(args.sector_size), 0)
-
-    fatfs = FATFS(size=partition_size, sector_size=sector_size_bytes)
-    fatfs.generate(input_dir)
     fatfs.write_filesystem(args.output_file)
+
+
+if __name__ == '__main__':
+    main()

components/fatfs/fatfsgen_utils/cluster.py

@@ -1,10 +1,13 @@
-# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 
 from typing import Optional
 
+from construct import Int16ul
+
 from .fatfs_state import FATFSState
-from .utils import build_byte, clean_first_half_byte, clean_second_half_byte, split_by_half_byte_12_bit_little_endian
+from .utils import (FAT12, FAT16, build_byte, clean_first_half_byte, clean_second_half_byte,
+                    split_by_half_byte_12_bit_little_endian)
 
 
 class Cluster:
@@ -13,7 +16,10 @@ class Cluster:
     """
     RESERVED_BLOCK_ID = 0
     ROOT_BLOCK_ID = 1
-    ALLOCATED_BLOCK_VALUE = 0xFFF  # for fat 12
+    ALLOCATED_BLOCK_FAT12 = 0xFFF
+    ALLOCATED_BLOCK_FAT16 = 0xFFFF
+    ALLOCATED_BLOCK_SWITCH = {FAT12: ALLOCATED_BLOCK_FAT12, FAT16: ALLOCATED_BLOCK_FAT16}
+    INITIAL_BLOCK_SWITCH = {FAT12: 0xFF8, FAT16: 0xFFF8}
 
     def __init__(self,
                  cluster_id: int,
@@ -26,7 +32,7 @@ class Cluster:
         self._next_cluster = None  # type: Optional[Cluster]
         if self.id == Cluster.RESERVED_BLOCK_ID:
             self.is_empty = False
-            self.set_in_fat(0xff8)
+            self.set_in_fat(self.INITIAL_BLOCK_SWITCH[self.fatfs_state.fatfs_type])
             return
 
         self.cluster_data_address = self._compute_cluster_data_address()
@@ -86,14 +92,16 @@ class Cluster:
         assert value <= (1 << self.fatfs_state.fatfs_type) - 1
         half_bytes = split_by_half_byte_12_bit_little_endian(value)
 
-        # hardcoded for fat 12
+        if self.fatfs_state.fatfs_type == FAT12:
-        # IDF-4046 will extend it for fat 16
             if self.fat_cluster_address % 8 == 0:
                 self.fatfs_state.binary_image[self.real_cluster_address] = build_byte(half_bytes[1], half_bytes[0])
                 self._set_second_half_byte(self.real_cluster_address + 1, half_bytes[2])
             elif self.fat_cluster_address % 8 != 0:
                 self._set_first_half_byte(self.real_cluster_address, half_bytes[0])
                 self.fatfs_state.binary_image[self.real_cluster_address + 1] = build_byte(half_bytes[2], half_bytes[1])
+        elif self.fatfs_state.fatfs_type == FAT16:
+            self.fatfs_state.binary_image[self.real_cluster_address:self.real_cluster_address + 2] = Int16ul.build(
+                value)
 
     @property
     def is_root(self) -> bool:
@@ -104,7 +112,7 @@ class Cluster:
         This method sets bits in FAT table to `allocated` and clean the corresponding sector(s)
         """
         self.is_empty = False
-        self.set_in_fat(Cluster.ALLOCATED_BLOCK_VALUE)
+        self.set_in_fat(self.ALLOCATED_BLOCK_SWITCH[self.fatfs_state.fatfs_type])
 
         cluster_start = self.cluster_data_address
         dir_size = self.fatfs_state.get_dir_size(self.is_root)

components/fatfs/fatfsgen_utils/exceptions.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 
 class WriteDirectoryException(Exception):
@@ -38,3 +38,7 @@ class WLNotInitialized(Exception):
 
 class FatalError(Exception):
     pass
+
+
+class InconsistentFATAttributes(Exception):
+    pass

components/fatfs/fatfsgen_utils/fat.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 
 from .cluster import Cluster
@@ -18,7 +18,7 @@ class FAT:
         self.reserved_sectors_cnt = reserved_sectors_cnt
 
         self.clusters = [Cluster(cluster_id=i, fatfs_state=self.fatfs_state) for i in
-                         range(1, self.fatfs_state.max_clusters)]
+                         range(1, self.fatfs_state.clusters)]
 
         # update root directory record
         self.clusters[0].allocate_cluster()

components/fatfs/fatfsgen_utils/fatfs_parser.py

@@ -0,0 +1,67 @@
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Apache-2.0
+from construct import Const, Int8ul, Int16ul, Int32ul, PaddedString, Struct
+
+from .utils import (BYTES_PER_DIRECTORY_ENTRY, get_fatfs_type, get_non_data_sectors_cnt, number_of_clusters,
+                    read_filesystem)
+
+
+class FATFSParser:
+    MAX_VOL_LAB_SIZE = 11
+    MAX_OEM_NAME_SIZE = 8
+    MAX_FS_TYPE_SIZE = 8
+
+    # the FAT specification defines 512 bytes for the boot sector header
+    BOOT_HEADER_SIZE = 512
+
+    BOOT_SECTOR_HEADER = Struct(
+        'BS_jmpBoot' / Const(b'\xeb\xfe\x90'),
+        'BS_OEMName' / PaddedString(MAX_OEM_NAME_SIZE, 'utf-8'),
+        'BPB_BytsPerSec' / Int16ul,
+        'BPB_SecPerClus' / Int8ul,
+        'BPB_RsvdSecCnt' / Int16ul,
+        'BPB_NumFATs' / Int8ul,
+        'BPB_RootEntCnt' / Int16ul,
+        'BPB_TotSec16' / Int16ul,
+        'BPB_Media' / Int8ul,
+        'BPB_FATSz16' / Int16ul,
+        'BPB_SecPerTrk' / Int16ul,
+        'BPB_NumHeads' / Int16ul,
+        'BPB_HiddSec' / Int32ul,
+        'BPB_TotSec32' / Int32ul,
+        'BS_DrvNum' / Const(b'\x80'),
+        'BS_Reserved1' / Const(b'\x00'),
+        'BS_BootSig' / Const(b'\x29'),
+        'BS_VolID' / Int32ul,
+        'BS_VolLab' / PaddedString(MAX_VOL_LAB_SIZE, 'utf-8'),
+        'BS_FilSysType' / PaddedString(MAX_FS_TYPE_SIZE, 'utf-8'),
+        'BS_EMPTY' / Const(448 * b'\x00'),
+        'Signature_word' / Const(b'\x55\xAA')
+    )
+    assert BOOT_SECTOR_HEADER.sizeof() == BOOT_HEADER_SIZE
+
+    def __init__(self, image_file_path: str, wl_support: bool = False) -> None:
+        if wl_support:
+            raise NotImplementedError('Parser is not implemented for WL yet.')
+        self.fatfs = read_filesystem(image_file_path)
+
+        # when wl is not supported we expect boot sector to be the first
+        self.parsed_header = FATFSParser.BOOT_SECTOR_HEADER.parse(self.fatfs[:FATFSParser.BOOT_HEADER_SIZE])
+
+    def print(self) -> None:
+        print('Properties of the FATFS:')
+        for key in self.parsed_header.keys():
+            if key in ('_io', 'BS_EMPTY', 'Signature_word'):
+                continue
+            print('  {}: {}'.format(key.replace('BPB_', '').replace('BS_', ''), self.parsed_header[key]))
+        root_dir_cnt = (self.parsed_header['BPB_RootEntCnt'] * BYTES_PER_DIRECTORY_ENTRY) // self.parsed_header[
+            'BPB_BytsPerSec']
+        non_data_sectors = get_non_data_sectors_cnt(self.parsed_header['BPB_RsvdSecCnt'],
+                                                    # this has to be changed when FAT32 is supported
+                                                    self.parsed_header['BPB_FATSz16'], root_dir_cnt)
+        data_clusters = self.parsed_header['BPB_TotSec16'] - non_data_sectors
+        clusters_num = number_of_clusters(data_clusters, self.parsed_header['BPB_SecPerClus'])
+        assert self.parsed_header['BPB_BytsPerSec'] in (512, 1024, 2048, 4096)
+        assert self.parsed_header['BPB_SecPerClus'] in (1, 2, 4, 8, 16, 32, 64, 128)
+        print(f'  Clusters number: {clusters_num}')
+        print(f'  FATFS type: FAT{get_fatfs_type(clusters_num)}')

components/fatfs/fatfsgen_utils/fatfs_state.py

@@ -1,16 +1,17 @@
-# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 
+from textwrap import dedent
+
+from .exceptions import InconsistentFATAttributes
+from .utils import (FAT12, FAT12_MAX_CLUSTERS, FAT16, FAT16_MAX_CLUSTERS, get_fatfs_type, get_non_data_sectors_cnt,
+                    number_of_clusters)
+
 
 class FATFSState:
     """
     The class represents the state and the configuration of the FATFS.
     """
-    FAT12_MAX_CLUSTERS = 4085
-    FAT16_MAX_CLUSTERS = 65525
-    FAT12 = 12
-    FAT16 = 16
-    FAT32 = 32
 
     def __init__(self,
                  entry_size: int,
@@ -28,7 +29,10 @@ class FATFSState:
                  num_heads: int,
                  hidden_sectors: int,
                  file_sys_type: str,
+                 explicit_fat_type: int = None,
                  long_names_enabled: bool = False):
+
+        self._explicit_fat_type = explicit_fat_type
         self._binary_image: bytearray = bytearray(b'')
         self.fat_tables_cnt: int = fat_tables_cnt
         self.oem_name: str = oem_name
@@ -47,6 +51,11 @@ class FATFSState:
         self.sectors_per_fat_cnt: int = sectors_per_fat
         self.sectors_per_cluster: int = sectors_per_cluster
 
+        if self.clusters in (FAT12_MAX_CLUSTERS, FAT16_MAX_CLUSTERS):
+            print('WARNING: It is not recommended to create FATFS with bounding '
+                  f'count of clusters: {FAT12_MAX_CLUSTERS} or {FAT16_MAX_CLUSTERS}')
+        self.check_fat_type()
+
     @property
     def binary_image(self) -> bytearray:
         return self._binary_image
@@ -68,28 +77,36 @@ class FATFSState:
 
     @property
     def non_data_sectors(self) -> int:
-        return self.reserved_sectors_cnt + self.sectors_per_fat_cnt + self.root_dir_sectors_cnt
+        return get_non_data_sectors_cnt(self.reserved_sectors_cnt, self.sectors_per_fat_cnt,  # type: ignore
+                                        self.root_dir_sectors_cnt)
 
     @property
     def data_region_start(self) -> int:
         return self.non_data_sectors * self.sector_size
 
     @property
-    def max_clusters(self) -> int:
+    def clusters(self) -> int:
-        return self.data_sectors // self.sectors_per_cluster
+        return number_of_clusters(self.data_sectors, self.sectors_per_cluster)  # type: ignore
 
     @property
     def root_directory_start(self) -> int:
         return (self.reserved_sectors_cnt + self.sectors_per_fat_cnt) * self.sector_size
 
+    def check_fat_type(self) -> None:
+        _type = self.fatfs_type
+        if self._explicit_fat_type is not None and self._explicit_fat_type != _type:
+            raise InconsistentFATAttributes(dedent(
+                f"""FAT type you specified is inconsistent with other attributes of the system.
+                    The specified FATFS type: FAT{self._explicit_fat_type}
+                    The actual FATFS type: FAT{_type}"""))
+        if _type not in (FAT12, FAT16):
+            raise NotImplementedError('FAT32 is currently not supported.')
+
     @property
     def fatfs_type(self) -> int:
-        if self.max_clusters < FATFSState.FAT12_MAX_CLUSTERS:
+        # variable typed_fatfs_type must be explicitly typed to avoid mypy error
-            return FATFSState.FAT12
+        typed_fatfs_type: int = get_fatfs_type(self.clusters)
-        elif self.max_clusters < FATFSState.FAT16_MAX_CLUSTERS:
+        return typed_fatfs_type
-            return FATFSState.FAT16
-        # fat is FAT.FAT32, not supported now
-        raise NotImplementedError('FAT32 is currently not supported.')
 
     @property
     def entries_root_count(self) -> int:

components/fatfs/fatfsgen_utils/utils.py

@@ -9,6 +9,13 @@ from typing import List, Optional, Tuple
 
 from construct import Int16ul
 
+FAT12_MAX_CLUSTERS: int = 4085
+FAT16_MAX_CLUSTERS: int = 65525
+FAT12: int = 12
+FAT16: int = 16
+FAT32: int = 32
+BYTES_PER_DIRECTORY_ENTRY = 32
+
 
 def crc32(input_values: List[int], crc: int) -> int:
     """
@@ -18,6 +25,22 @@ def crc32(input_values: List[int], crc: int) -> int:
     return binascii.crc32(bytearray(input_values), crc)
 
 
+def number_of_clusters(number_of_sectors: int, sectors_per_cluster: int) -> int:
+    return number_of_sectors // sectors_per_cluster
+
+
+def get_non_data_sectors_cnt(reserved_sectors_cnt: int, sectors_per_fat_cnt: int, root_dir_sectors_cnt: int) -> int:
+    return reserved_sectors_cnt + sectors_per_fat_cnt + root_dir_sectors_cnt
+
+
+def get_fatfs_type(clusters_count: int) -> int:
+    if clusters_count < FAT12_MAX_CLUSTERS:
+        return FAT12
+    if clusters_count < FAT16_MAX_CLUSTERS:
+        return FAT16
+    return FAT32
+
+
 def required_clusters_count(cluster_size: int, content: bytes) -> int:
     # compute number of required clusters for file text
     return (len(content) + cluster_size - 1) // cluster_size
@@ -88,8 +111,35 @@ def get_args_for_partition_generator(desc: str) -> argparse.Namespace:
                         help='Size of the partition in bytes')
     parser.add_argument('--sector_size',
                         default=4096,
+                        type=int,
+                        choices=[512, 1024, 2048, 4096],
                         help='Size of the partition in bytes')
+    parser.add_argument('--sectors_per_cluster',
+                        default=1,
+                        type=int,
+                        choices=[1, 2, 4, 8, 16, 32, 64, 128],
+                        help='Number of sectors per cluster')
+    parser.add_argument('--root_entry_count',
+                        default=512,
+                        help='Number of entries in the root directory')
+    parser.add_argument('--fat_type',
+                        default=0,
+                        type=int,
+                        choices=[12, 16, 0],
+                        help="""
+                        Type of fat. Select 12 for fat12, 16 for fat16. Don't set, or set to 0 for automatic
+                        calculation using cluster size and partition size.
+                        """)
+
     args = parser.parse_args()
+    if args.fat_type == 0:
+        args.fat_type = None
+    args.partition_size = int(str(args.partition_size), 0)
     if not os.path.isdir(args.input_directory):
         raise NotADirectoryError(f'The target directory `{args.input_directory}` does not exist!')
     return args
+
+
+def read_filesystem(path: str) -> bytearray:
+    with open(path, 'rb') as fs_file:
+        return bytearray(fs_file.read())

components/fatfs/project_include.cmake

@@ -16,6 +16,43 @@ function(fatfs_create_partition_image partition base_dir)
         set(fatfsgen_py ${python} ${idf_path}/components/fatfs/fatfsgen.py)
     endif()
 
+    if("${CONFIG_FATFS_SECTORS_PER_CLUSTER_1}")
+        set(sectors_per_cluster 1)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_2}")
+        set(sectors_per_cluster 2)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_4}")
+        set(sectors_per_cluster 4)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_8}")
+        set(sectors_per_cluster 8)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_16}")
+        set(sectors_per_cluster 16)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_32}")
+        set(sectors_per_cluster 32)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_64}")
+        set(sectors_per_cluster 64)
+    elseif("${CONFIG_FATFS_SECTORS_PER_CLUSTER_128}")
+        set(sectors_per_cluster 128)
+    endif()
+
+    if("${CONFIG_FATFS_SECTOR_512}")
+        set(fatfs_sector_size 512)
+    elseif("${CONFIG_FATFS_SECTOR_1024}")
+        set(fatfs_sector_size 1024)
+    elseif("${CONFIG_FATFS_SECTOR_2048}")
+        set(fatfs_sector_size 2048)
+    else()
+        set(fatfs_sector_size 4096)
+    endif()
+
+
+    if("${CONFIG_FATFS_AUTO_TYPE}")
+        set(fatfs_explicit_type 0)
+    elseif("${CONFIG_FATFS_FAT12}")
+        set(fatfs_explicit_type 12)
+    elseif("${CONFIG_FATFS_FAT16}")
+        set(fatfs_explicit_type 16)
+    endif()
+
     get_filename_component(base_dir_full_path ${base_dir} ABSOLUTE)
     partition_table_get_partition_info(size "--partition-name ${partition}" "size")
     partition_table_get_partition_info(offset "--partition-name ${partition}" "offset")
@@ -28,6 +65,9 @@ function(fatfs_create_partition_image partition base_dir)
             COMMAND ${fatfsgen_py} ${base_dir_full_path}
             --partition_size ${size}
             --output_file ${image_file}
+            --sector_size "${fatfs_sector_size}"
+            --sectors_per_cluster "${sectors_per_cluster}"
+            --fat_type "${fatfs_explicit_type}"
             )
 
         set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" APPEND PROPERTY

components/fatfs/test_fatfsgen/test_fatfsgen.py

@@ -7,12 +7,14 @@ import shutil
 import sys
 import unittest
 
-from test_utils import CFG, generate_test_dir_1, generate_test_dir_2
+from test_utils import CFG, fill_sector, generate_test_dir_1, generate_test_dir_2
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
-import fatfsgen  # noqa E402
+import fatfsgen  # noqa E402  # pylint: disable=C0413
-from fatfsgen_utils.exceptions import WriteDirectoryException  # noqa E402
+from fatfsgen_utils.exceptions import TooLongNameException  # noqa E402  # pylint: disable=C0413
-from fatfsgen_utils.exceptions import LowerCaseException, NoFreeClusterException, TooLongNameException  # noqa E402
+from fatfsgen_utils.exceptions import WriteDirectoryException  # noqa E402  # pylint: disable=C0413
+from fatfsgen_utils.exceptions import LowerCaseException, NoFreeClusterException  # noqa E402  # pylint: disable=C0413
+from fatfsgen_utils.utils import read_filesystem  # noqa E402  # pylint: disable=C0413
 
 
 class FatFSGen(unittest.TestCase):
@@ -27,8 +29,9 @@ class FatFSGen(unittest.TestCase):
     def test_empty_file_sn_fat12(self) -> None:
         fatfs = fatfsgen.FATFS()
         fatfs.create_file('TESTFILE')
+
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2000:0x200c], b'TESTFILE   \x20')  # check entry name and type
         self.assertEqual(file_system[0x1000:0x1006], b'\xf8\xff\xff\xff\x0f\x00')  # check fat
@@ -37,7 +40,7 @@ class FatFSGen(unittest.TestCase):
         fatfs = fatfsgen.FATFS()
         fatfs.create_directory('TESTFOLD')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2000:0x200c], b'TESTFOLD   \x10')  # check entry name and type
         self.assertEqual(file_system[0x1000:0x1006], b'\xf8\xff\xff\xff\x0f\x00')  # check fat
@@ -48,7 +51,7 @@ class FatFSGen(unittest.TestCase):
         fatfs = fatfsgen.FATFS()
         fatfs.create_file('TESTF', extension='TXT')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x2000:0x200c], b'TESTF   TXT\x20')  # check entry name and type
         self.assertEqual(file_system[0x1000:0x1006], b'\xf8\xff\xff\xff\x0f\x00')  # check fat
 
@@ -57,7 +60,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT')
         fatfs.write_content(path_from_root=['WRITEF.TXT'], content=b'testcontent')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2000:0x200c], b'WRITEF  TXT\x20')  # check entry name and type
         self.assertEqual(file_system[0x201a:0x2020], b'\x02\x00\x0b\x00\x00\x00')  # check size and cluster ref
@@ -70,7 +73,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT', path_from_root=['TESTFOLD'])
         fatfs.write_content(path_from_root=['TESTFOLD', 'WRITEF.TXT'], content=b'testcontent')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2000:0x200c], b'TESTFOLD   \x10')
         self.assertEqual(
@@ -91,7 +94,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.fat.clusters[3].set_in_fat(4)
         fatfs.fat.clusters[4].set_in_fat(5)
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(
             file_system[0x1000:0x1010],
             b'\xf8\xff\xff\xe8\x43\x00\x05\xf0\xff\xff\x0f\x00\x00\x00\x00\x00')
@@ -101,7 +104,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT')
         fatfs.write_content(path_from_root=['WRITEF.TXT'], content=CFG['sector_size'] * b'a')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x1000: 0x100e], b'\xf8\xff\xff\xff\x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00')
         self.assertEqual(file_system[0x6000: 0x7000], CFG['sector_size'] * b'a')
 
@@ -110,7 +113,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT')
         fatfs.write_content(path_from_root=['WRITEF.TXT'], content=CFG['sector_size'] * b'a' + b'a')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x1000: 0x100e], b'\xf8\xff\xff\x03\xf0\xff\x00\x00\x00\x00\x00\x00\x00\x00')
         self.assertEqual(file_system[0x7000: 0x8000], b'a' + (CFG['sector_size'] - 1) * b'\x00')
 
@@ -118,12 +121,11 @@ class FatFSGen(unittest.TestCase):
         fatfs = fatfsgen.FATFS()
         fatfs.create_directory('TESTFOLD')
 
-        for i in range(CFG['sector_size'] // CFG['entry_size']):
+        fill_sector(fatfs)
-            fatfs.create_file(f'A{str(i).upper()}', path_from_root=['TESTFOLD'])
         fatfs.write_content(path_from_root=['TESTFOLD', 'A0'], content=b'first')
         fatfs.write_content(path_from_root=['TESTFOLD', 'A126'], content=b'later')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x1000: 0x10d0],
                          b'\xf8\xff\xff\x82\xf0\xff' + 192 * b'\xff' + 10 * b'\x00')
         self.assertEqual(file_system[0x85000:0x85005], b'later')
@@ -162,7 +164,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.write_content(path_from_root=['TESTFOLD', 'A253'], content=b'later')
         fatfs.write_content(path_from_root=['TESTFOLD', 'A255'], content=b'last')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x105000:0x105010], b'later\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
         self.assertEqual(file_system[0x108000:0x108010], b'last\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 
@@ -193,7 +195,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT', path_from_root=['TESTFOLD', 'TESTFOLL', 'TESTFOLO'])
         fatfs.write_content(path_from_root=['TESTFOLD', 'TESTFOLL', 'TESTFOLO', 'WRITEF.TXT'], content=b'later')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x9000:0x9010], b'later\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 
@@ -205,7 +207,7 @@ class FatFSGen(unittest.TestCase):
         fatfs.create_file('WRITEF', extension='TXT', path_from_root=['TESTFOLD', 'TESTFOLD', 'TESTFOLD'])
         fatfs.write_content(path_from_root=['TESTFOLD', 'TESTFOLD', 'TESTFOLD', 'WRITEF.TXT'], content=b'later')
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2000:0x2010], b'TESTFOLD   \x10\x00\x00\x01\x00')
         self.assertEqual(file_system[0x2010:0x2020], b'!\x00\x00\x00\x00\x00\x01\x00\x01\x00\x02\x00\x00\x00\x00\x00')
@@ -220,7 +222,7 @@ class FatFSGen(unittest.TestCase):
         fatfs = fatfsgen.FATFS()
         fatfs.generate(CFG['test_dir'])
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
         self.assertEqual(file_system[0x6060:0x6070], b'TESTFIL2    \x00\x00\x01\x00')
         self.assertEqual(file_system[0x6070:0x6080], b'!\x00\x00\x00\x00\x00\x01\x00\x01\x00\x05\x00\x0b\x00\x00\x00')
         self.assertEqual(file_system[0x7040:0x7050], b'LASTFILE    \x00\x00\x01\x00')
@@ -232,7 +234,7 @@ class FatFSGen(unittest.TestCase):
         fatfs = fatfsgen.FATFS()
         fatfs.generate(CFG['test_dir2'])
         fatfs.write_filesystem(CFG['output_file'])
-        file_system = fatfs.read_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
 
         self.assertEqual(file_system[0x2020:0x2030], b'TESTFILE    \x00\x00\x01\x00')
         self.assertEqual(file_system[0x6060:0x6070], b'TESTFIL2    \x00\x00\x01\x00')
@@ -243,6 +245,43 @@ class FatFSGen(unittest.TestCase):
         self.assertEqual(file_system[0xa000:0xa010], b'ahoj\n\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
         self.assertEqual(file_system[0xb000:0xb009], b'\xff\xff\xff\xff\xff\xff\xff\xff\xff')
 
+    def test_empty_fat16(self) -> None:
+        fatfs = fatfsgen.FATFS(size=17 * 1024 * 1024)
+        fatfs.write_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
+        self.assertEqual(file_system[0x1000:0x1007], b'\xf8\xff\xff\xff\x00\x00\x00')
+
+    def test_simple_fat16(self) -> None:
+        fatfs = fatfsgen.FATFS(size=17 * 1024 * 1024)
+        fatfs.create_directory('TESTFOLD')
+        fatfs.write_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
+        self.assertEqual(file_system[0x1000:0x1007], b'\xf8\xff\xff\xff\xff\xff\x00')
+
+    def test_chaining_fat16(self) -> None:
+        fatfs = fatfsgen.FATFS(size=17 * 1024 * 1024)
+        fatfs.create_file('WRITEF', extension='TXT')
+        fatfs.write_content(path_from_root=['WRITEF.TXT'], content=CFG['sector_size'] * b'a' + b'a')
+        fatfs.write_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
+        self.assertEqual(file_system[0x1000: 0x100e], b'\xf8\xff\xff\xff\x03\x00\xff\xff\x00\x00\x00\x00\x00\x00')
+        self.assertEqual(file_system[0x7000: 0x8000], b'a' + (CFG['sector_size'] - 1) * b'\x00')
+
+    def test_full_sector_folder_fat16(self) -> None:
+        fatfs = fatfsgen.FATFS(size=17 * 1024 * 1024)
+        fatfs.create_directory('TESTFOLD')
+
+        fill_sector(fatfs)
+        fatfs.write_content(path_from_root=['TESTFOLD', 'A0'], content=b'first')
+        fatfs.write_content(path_from_root=['TESTFOLD', 'A126'], content=b'later')
+        fatfs.write_filesystem(CFG['output_file'])
+        file_system = read_filesystem(CFG['output_file'])
+        self.assertEqual(file_system[0x1000: 0x1110],
+                         b'\xf8\xff\xff\xff\x82\x00' + 258 * b'\xff' + 8 * b'\x00')
+        self.assertEqual(file_system[0x85000:0x85005], b'later')
+        self.assertEqual(file_system[0x86000:0x86010], b'A126        \x00\x00\x01\x00')
+        self.assertEqual(file_system[0x86020:0x86030], b'A127        \x00\x00\x01\x00')
+
 
 if __name__ == '__main__':
     unittest.main()

components/fatfs/test_fatfsgen/test_utils.py

@@ -1,8 +1,12 @@
-# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Apache-2.0
 import os
+import sys
 from typing import Any, Dict, Union
 
+sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
+import fatfsgen  # noqa E402  # pylint: disable=C0413
+
 CFG = dict(
     sector_size=4096,
     entry_size=32,
@@ -33,3 +37,8 @@ def generate_test_dir_2() -> None:
         file.write('thisistest\n')
     with open(os.path.join(CFG['test_dir2'], 'testfile'), 'w') as file:
         file.write('ahoj\n')
+
+
+def fill_sector(fatfs: fatfsgen.FATFS) -> None:
+    for i in range(CFG['sector_size'] // CFG['entry_size']):
+        fatfs.create_file(f'A{str(i).upper()}', path_from_root=['TESTFOLD'])

components/fatfs/wl_fatfsgen.py

@@ -52,7 +52,7 @@ class WLFATFS:
                  sectors_per_cluster: int = 1,
                  sector_size: int = 0x1000,
                  sectors_per_fat: int = 1,
-                 root_dir_sectors_cnt: int = 4,
+                 explicit_fat_type: int = None,
                  hidden_sectors: int = 0,
                  long_names_enabled: bool = False,
                  entry_size: int = 32,
@@ -63,8 +63,9 @@ class WLFATFS:
                  file_sys_type: str = 'FAT',
                  version: int = 2,
                  temp_buff_size: int = 32,
-                 updaterate: int = 16,
+                 update_rate: int = 16,
                  device_id: int = None,
+                 root_entry_count: int = 512,
                  media_type: int = 0xf8) -> None:
         if sector_size != WLFATFS.WL_SECTOR_SIZE:
             raise NotImplementedError(f'The only supported sector size is currently {WLFATFS.WL_SECTOR_SIZE}')
@@ -74,7 +75,7 @@ class WLFATFS:
         self._version = version
         self._temp_buff_size = temp_buff_size
         self._device_id = device_id
-        self._updaterate = updaterate
+        self._update_rate = update_rate
         self.partition_size = size
         self.total_sectors = self.partition_size // self.sector_size
         self.wl_state_size = WLFATFS.WL_STATE_HEADER_SIZE + WLFATFS.WL_STATE_RECORD_SIZE * self.total_sectors
@@ -89,13 +90,14 @@ class WLFATFS:
         self.plain_fat_sectors = self.total_sectors - wl_sectors
 
         self.plain_fatfs = FATFS(
+            explicit_fat_type=explicit_fat_type,
             size=self.plain_fat_sectors * self.sector_size,
             reserved_sectors_cnt=reserved_sectors_cnt,
             fat_tables_cnt=fat_tables_cnt,
             sectors_per_cluster=sectors_per_cluster,
             sector_size=sector_size,
             sectors_per_fat=sectors_per_fat,
-            root_dir_sectors_cnt=root_dir_sectors_cnt,
+            root_entry_count=root_entry_count,
             hidden_sectors=hidden_sectors,
             long_names_enabled=long_names_enabled,
             entry_size=entry_size,
@@ -127,7 +129,7 @@ class WLFATFS:
                 full_mem_size=self.partition_size,
                 page_size=self.sector_size,
                 sector_size=self.sector_size,
-                updaterate=self._updaterate,
+                updaterate=self._update_rate,
                 wr_size=16,
                 version=self._version,
                 temp_buff_size=self._temp_buff_size
@@ -149,7 +151,7 @@ class WLFATFS:
                 max_pos=self.plain_fat_sectors + WLFATFS.DUMMY_SECTORS_COUNT,
                 move_count=0,
                 access_count=0,
-                max_count=self._updaterate,
+                max_count=self._update_rate,
                 block_size=self.sector_size,
                 version=self._version,
                 device_id=self._device_id or generate_4bytes_random(),
@@ -187,12 +189,13 @@ class WLFATFS:
 if __name__ == '__main__':
     desc = 'Create a FAT filesystem with support for wear levelling and populate it with directory content'
     args = get_args_for_partition_generator(desc)
-    input_dir = args.input_directory
 
-    partition_size = int(str(args.partition_size), 0)
+    wl_fatfs = WLFATFS(sector_size=args.sector_size,
-    sector_size_bytes = int(str(args.sector_size), 0)
+                       sectors_per_cluster=args.sectors_per_cluster,
+                       size=args.partition_size,
+                       root_entry_count=args.root_entry_count,
+                       explicit_fat_type=args.fat_type)
 
-    wl_fatfs = WLFATFS(size=partition_size, sector_size=sector_size_bytes)
+    wl_fatfs.wl_generate(args.input_directory)
-    wl_fatfs.wl_generate(input_dir)
     wl_fatfs.init_wl()
     wl_fatfs.wl_write_filesystem(args.output_file)

docs/en/api-reference/storage/fatfs.rst

@@ -95,7 +95,7 @@ The tool is used to create filesystem images on a host and populate it with cont
 
 The script is based on the partition generator (:component_file:`fatfsgen.py<fatfs/fatfsgen.py>`) and except for generating partition also initializes wear levelling.
 
-Current implementation supports short file names and FAT12. Long file names, and FAT16 are subjects of the future work.
+Current implementation supports short file names, FAT12 and FAT16. Long file names support is the subject of the future work.
 
 
 Build system integration with FATFS partition generator