Problem with first connection to external storage using littlefs and nRF Connect SDK 2.6.0

[Tomasz Chudy]

Let me point out that when compiling on nRF Connect SDK 2.5.0, everything works perfectly.

This always happens when the external memory is not initialized yet. I have several of my own prototype boards and the same thing happens on the new nrf52840dk board.

I configure littlefs like this:

in proj.conf:

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CONFIG_FILE_SYSTEM=y

CONFIG_FILE_SYSTEM_LITTLEFS=y

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CONFIG_FILE_SYSTEM=y
CONFIG_FILE_SYSTEM_LITTLEFS=y

In pm_static.yml

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external_flash:

address: 0x0

end_address: 0x800000

region: external_flash

size: 0x800000

littlefs_storage:

address: 0x0

end_address: 0x800000

region: external_flash

size: 0x800000

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external_flash:
  address: 0x0
  end_address: 0x800000
  region: external_flash
  size: 0x800000
littlefs_storage:
  address: 0x0
  end_address: 0x800000
  region: external_flash
  size: 0x800000

I use mcuboot so in child_image/mcuboot.conf

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CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n

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CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n

In code:

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FS_LITTLEFS_DECLARE_DEFAULT_CONFIG (storage_data);

static const struct device *storage_dev = NULL;

static struct fs_mount_t mnt_storage =

{

.type = FS_LITTLEFS,

.fs_data = &storage_data,

.storage_dev = (void *)FLASH_AREA_ID(LITTLEFS_STORAGE),

.mnt_point = "/lfs",

};

void storage_init ()

{

storage_dev = DEVICE_DT_GET (DT_NODELABEL (mx25r64));

if (storage_dev != NULL)

{

printk ("[Storage] Device is found\n");

int res = fs_mount (&mnt_storage);

if (res == 0)

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FS_LITTLEFS_DECLARE_DEFAULT_CONFIG (storage_data);

static const struct device *storage_dev = NULL;

static struct fs_mount_t mnt_storage =
{
	.type = FS_LITTLEFS,
	.fs_data = &storage_data,
	.storage_dev = (void *)FLASH_AREA_ID(LITTLEFS_STORAGE),
	.mnt_point = "/lfs",
};

void storage_init ()
{
    storage_dev = DEVICE_DT_GET (DT_NODELABEL (mx25r64));
    if (storage_dev != NULL)
    {
        printk ("[Storage] Device is found\n");

    	int res = fs_mount (&mnt_storage);
        if (res == 0)
        {
            printf("[Storage] Mounted\n");
            
            res = fs_unmount (&mnt_storage);
            if (res == 0)
            {
                printf("[Storage] Unmounted\n");
            }
            else
            {
                printf("[Storage] Error unmounting: %d\n", res);
            }
        }
        else
        {
            printf("[Storage] Error mounting: %d\n", res);
        }
    }
    else
    {
        printk ("[Storage] Device not found\n");
    }
}

When I compile on SDK 2.5.0, everything is always OK.
When I compile on SDK 2.6.0, I always get error -19 with the fs_mount function, i.e.: ENODEV 19 /* No such device */ (but only if the memory has never been initialized)

Interestingly, when I compile on SDK 2.5.0 and start the memory, it initializes itself correctly, then when I compile on SDK 2.6.0, everything will work correctly, because the memory has already been initialized on 2.5.0. So the problem is only with the first initialization when using the fs_mount function on SDK 2.6.0.

Has something changed in SDK 2.6.0 that requires adding some configuration to be able to initialize external storage from littlefs?

Or do I need to add some flag to the fs_mount_t.flags structure?