1/* 2 * volume_id - reads filesystem label and uuid 3 * 4 * Copyright (C) 2018 Sven-Göran Bergh <sgb@systemaxion.se> 5 * 6 * Licensed under GPLv2, see file LICENSE in this source tree. 7 */ 8//config:config FEATURE_VOLUMEID_LFS 9//config: bool "LittleFS filesystem" 10//config: default y 11//config: depends on VOLUMEID && FEATURE_BLKID_TYPE 12//config: help 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 17//config: layer. 18 19//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_LFS) += lfs.o 20 21#include "volume_id_internal.h" 22 23#define LFS_SB1_OFFSET 0x10 24#define LFS_MAGIC_NAME "littlefs" 25#define LFS_MAGIC_LEN 8 26 27// The superblock is stored in the first metadata pair, i.e the first two blocks. 28struct 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 43} PACKED; 44 45int FAST_FUNC volume_id_probe_lfs(struct volume_id *id /*,uint64_t off*/) 46{ 47 struct lfs_super_block *sb; 48 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)); 52 53 if (!sb) 54 return -1; 55 56 if (memcmp(sb->magic, LFS_MAGIC_NAME, LFS_MAGIC_LEN) != 0) 57 return -1; 58 59 IF_FEATURE_BLKID_TYPE(id->type = LFS_MAGIC_NAME); 60 61 return 0; 62} 63