STM32

ARM面向IoT推出Littlefs，并对比了FATfs

2019-12-12 18:21发布

站内问答 / STM32/STM8
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File systems for embedded systems and IoT devices have some additional requirements:

Power-cut resilience - it requires strong guarantees that the file system remains consistent, and data is flushed to the underlying storage.
Wear-leveling - typically storage supports a limited number of erases per block, so making use of the entire storage device is important for reliability.
Tiny footprint - IoT devices are constrained by ROM and RAM. A small footprint saves money.




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72条回答
lindabell
2019-12-17 13:17
用Qt试了一下，仅仅试一试；
用数组来模拟falsh的。

  1. #include "lfs.h"
  2. #include "lfs_emubd.h"
  3. #include "lfs_ram.h"
  4. // variables used by the filesystem
  5. lfs_t lfs;
  6. lfs_file_t file;

  8. // configuration of the filesystem is provided by this struct
  9. struct lfs_config cfg = {
  10.     // block device operations
  11.     .read  = lfs_ram_read,
  12.     .prog  = lfs_ram_prog,
  13.     .erase = lfs_ram_erase,
  14.     .sync  = lfs_ram_sync,

  16.     // block device configuration
  17.     .read_size = 16,
  18.     .prog_size = 16,
  19.     .block_size = 1024,
  20.     .block_count =10240,
  21.     .lookahead = 128,
  22.     .context=&cfg,
  23. };

  25. // entry point
  26. int main(void)
  27. {


  30.     // mount the filesystem
  31.     int err = lfs_mount(&lfs, &cfg);

  33.     // reformat if we can't mount the filesystem
  34.     // this should only happen on the first boot
  35.     if (err) {
  36.         lfs_format(&lfs, &cfg);
  37.         lfs_mount(&lfs, &cfg);
  38.     }

  40.     // read current count
  41.     uint32_t boot_count = 0;
  42.     lfs_file_open(&lfs, &file, "boot_count", LFS_O_RDWR | LFS_O_CREAT);
  43.     lfs_file_read(&lfs, &file, &boot_count, sizeof(boot_count));

  45.     // update boot count
  46.     boot_count += 1;
  47.     lfs_file_rewind(&lfs, &file);
  48.     lfs_file_write(&lfs, &file, &boot_count, sizeof(boot_count));

  50.     // remember the storage is not updated until the file is closed successfully
  51.     lfs_file_close(&lfs, &file);

  53.     // release any resources we were using
  54.     lfs_unmount(&lfs);

  56.     // print the boot count
  57.     printf("boot_count: %d ", boot_count);


  60.     //test
  61.     boot_count=0;
  62.     lfs_mount(&lfs, &cfg);
  63.     lfs_file_open(&lfs, &file, "boot_count", LFS_O_RDWR | LFS_O_CREAT);
  64.     lfs_file_read(&lfs, &file, &boot_count, sizeof(boot_count));
  65.     printf("boot_count: %d ", boot_count);
  66.     boot_count++;
  67.     lfs_file_rewind(&lfs, &file);
  68.     lfs_file_write(&lfs, &file, &boot_count, sizeof(boot_count));
  69.     lfs_file_close(&lfs, &file);
  70.     lfs_unmount(&lfs);

  72.     //test
  73.     boot_count=0;
  74.     lfs_mount(&lfs, &cfg);
  75.     lfs_file_open(&lfs, &file, "boot_count", LFS_O_RDWR | LFS_O_CREAT);
  76.     lfs_file_read(&lfs, &file, &boot_count, sizeof(boot_count));
  77.     printf("boot_count: %d ", boot_count);
  78.     boot_count++;
  79.     lfs_file_rewind(&lfs, &file);
  80.     lfs_file_write(&lfs, &file, &boot_count, sizeof(boot_count));
  81.     lfs_file_close(&lfs, &file);
  82.     lfs_unmount(&lfs);

  84.     //test
  85.     boot_count=0;
  86.     lfs_mount(&lfs, &cfg);
  87.     lfs_file_open(&lfs, &file, "boot_count", LFS_O_RDWR | LFS_O_CREAT);
  88.     lfs_file_read(&lfs, &file, &boot_count, sizeof(boot_count));
  89.     printf("boot_count: %d ", boot_count);
  90.     boot_count++;
  91.     lfs_file_rewind(&lfs, &file);
  92.     lfs_file_write(&lfs, &file, &boot_count, sizeof(boot_count));
  93.     lfs_file_close(&lfs, &file);
  94.     lfs_unmount(&lfs);

  96. }
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