2 * volume_id - reads filesystem label and uuid
4 * Copyright (C) 2018 Sven-Göran Bergh <sgb@systemaxion.se>
6 * Licensed under GPLv2, see file LICENSE in this source tree.
8 //config:config FEATURE_VOLUMEID_LFS
9 //config: bool "LittleFS filesystem"
11 //config: depends on VOLUMEID && FEATURE_BLKID_TYPE
13 //config: LittleFS is a small fail-safe filesystem designed for embedded
14 //config: systems. It has strong copy-on-write guarantees and storage on disk
15 //config: is always kept in a valid state. It also provides a form of dynamic
16 //config: wear levelling for systems that can not fit a full flash translation
19 //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_LFS) += lfs.o
21 #include "volume_id_internal.h"
23 #define LFS_SB1_OFFSET 0x10
24 #define LFS_MAGIC_NAME "littlefs"
25 #define LFS_MAGIC_LEN 8
27 // The superblock is stored in the first metadata pair, i.e the first two blocks.
28 struct lfs_super_block { // A block in a metadata pair
29 // /* 0x00 */ uint32_t rev_count; // Revision count
30 // /* 0x04 */ uint32_t dir_size; // Directory size
31 // /* 0x08 */ uint64_t tail_ptr; // Tail pointer
32 /* 0x10 */ uint8_t entry_type; // Entry type
33 /* 0x11 */ uint8_t entry_len; // Entry length
34 /* 0x12 */ uint8_t att_len; // Attribute length
35 /* 0x13 */ uint8_t name_len; // Name length
36 /* 0x14 */ uint64_t root_dir; // Root directory
37 /* 0x1C */ uint32_t block_size; // Block size
38 /* 0x20 */ uint32_t block_count; // Block count
39 /* 0x24 */ uint16_t ver_major; // Version major
40 /* 0x26 */ uint16_t ver_minor; // Version minor
41 /* 0x28 */ uint8_t magic[LFS_MAGIC_LEN]; // Magic string "littlefs"
42 // /* 0x30 */ uint32_t crc; // CRC-32 checksum
45 int FAST_FUNC volume_id_probe_lfs(struct volume_id *id /*,uint64_t off*/)
47 struct lfs_super_block *sb;
49 // Go for primary super block (ignore second sb)
50 dbg("lfs: probing at offset 0x%x", LFS_SB1_OFFSET);
51 sb = volume_id_get_buffer(id, LFS_SB1_OFFSET, sizeof(*sb));
56 if (memcmp(sb->magic, LFS_MAGIC_NAME, LFS_MAGIC_LEN) != 0)
59 IF_FEATURE_BLKID_TYPE(id->type = LFS_MAGIC_NAME);