Mount LittleFS to both internal & external flash

RE: Mount LittleFS to both internal & external flash

Aurele — Fri, 30 May 2025 08:41:13 GMT

Hello clockis
I'm encountering the same issue — did you happen to find a solution?
Regards,
Aurélien

RE: Mount LittleFS to both internal & external flash

mluo — Sat, 04 Nov 2023 01:54:37 GMT

I am very interested in a possible solution.

RE: Mount LittleFS to both internal & external flash

GiorgioG — Fri, 03 Nov 2023 17:45:22 GMT

Hi, sorry to get into this conversation; I have the same problem, the same flash and the same micro, and I am very interested in a possible solution.

RE: Mount LittleFS to both internal & external flash

clockis — Wed, 01 Nov 2023 15:08:32 GMT

Hello Sigurd,

I did try all combinations of defining the mount point with the CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y enabled but I still get a mounting error for the external flash storage ( the internal flash is mounted successfully).

Could you please provide some feedback on the following questions:

Is it possible to mount one instance of the LittleFS system in the internal flash and in the same application (simultaneously) mount a second instance of the LittleFS system in the external SPI NOR flash?
Could you please send some code or some more specific information on which way the mounting needs to be set-up, using the FSTAB entries or manually?
Also what about the .dts file do I need to just define the flash memory subnode in the spi node as shown below or do I need to add the partition property to it as shown in the second segment below:

Just the flash memory node:

&spi1{
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = < &gpio0 26 GPIO_ACTIVE_LOW >;

	w25q512nw: w25q512nw@0 {
		compatible = "jedec,spi-nor";
		status = "okay";
		label = "W25Q512NW";
		wp-gpios = <&gpio0 30 GPIO_ACTIVE_LOW>;
		hold-gpios = <&gpio0 14 GPIO_ACTIVE_LOW>;
		reg = < 0 >;
		spi-max-frequency = < 8000000 >;
		jedec-id = [ ef 60 20 ]; // Manufacturer ID = EFh, Memory Type (ID15-ID8) = 60h and Capacity (ID7-ID0) = 20h 
		size = < 536870912 >;    // Flash capacity in bits = 512M-bit = 1024 * 1024 * 512 * 1bit = 536870912 bit
		has-dpd;
		t-enter-dpd = < 3000 >;  // in nanoseconds - The power-down state will entered within the time duration of tDP: 3us 
		t-exit-dpd = < 30000 >;  // in nanoseconds - The Release from power-down will take the time duration of tRES1: 30us
	};
};

The flash memory node with the partition property as shown in the post you linked

&spi1{
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = < &gpio0 26 GPIO_ACTIVE_LOW >;

	w25q512nw: w25q512nw@0 {
		compatible = "jedec,spi-nor";
		status = "okay";
		label = "W25Q512NW";
		wp-gpios = <&gpio0 30 GPIO_ACTIVE_LOW>;
		hold-gpios = <&gpio0 14 GPIO_ACTIVE_LOW>;
		reg = < 0 >;
		spi-max-frequency = < 8000000 >;
		jedec-id = [ ef 60 20 ]; // Manufacturer ID = EFh, Memory Type (ID15-ID8) = 60h and Capacity (ID7-ID0) = 20h 
		size = < 536870912 >;    // Flash capacity in bits = 512M-bit = 1024 * 1024 * 512 * 1bit = 536870912 bit
		has-dpd;
		t-enter-dpd = < 3000 >;  // in nanoseconds - The power-down state will entered within the time duration of tDP: 3us 
		t-exit-dpd = < 30000 >;  // in nanoseconds - The Release from power-down will take the time duration of tRES1: 30us
	    partitions {
			compatible = "fixed-partitions";
			#address-cells = <1>;
			#size-cells = <1>;
			/* 64 MB partition to use for LFS filesystem */
			ext_storage_partition: partition@0000000 {
				label = "external_flash";
				reg = <0x0000000 0x2000000>;
			};
		};
	};
};

I also assumed this piece for the .dts is necessary, please confirm.

chosen {
		nordic,pm-ext-flash = &w25q512nw;
	};

For the mount point definition(for the external flash) in the code so I need to define using the FSTAB entry or the manual entry? For the manual entry, what do I need to put in the .storage_dev field?

FS_LITTLEFS_DECLARE_DEFAULT_CONFIG(_LfsConfig);
static struct fs_mount_t lfs_storage_mnt = {
	.type = FS_LITTLEFS,
	.fs_data = &_LfsConfig,
	// .storage_dev = (void *)FLASH_AREA_LABEL_STR(external_flash),
	.storage_dev = (void *)FLASH_AREA_ID(external_flash),
	.mnt_point = "/lfs2",
};

static struct fs_mount_t *mp = &lfs_storage_mnt;

The internal flash is set up successfully using the following definition of the mount point. Could this definition create conflicts with the external flash definition of the mount point?:

FS_LITTLEFS_DECLARE_DEFAULT_CONFIG(_Lfs1Config);
static struct fs_mount_t lfs_storage_mnt = {
	.type = FS_LITTLEFS,
	.fs_data = &_Lfs1Config,
	.storage_dev = (void *)FLASH_AREA_ID(storage),
	.mnt_point = "/lfs1",
};

static	struct fs_mount_t *mp =	&lfs_storage_mnt;

For the prj file I have the following, please confirm if any config options are missing or need to be changed?

# Flash File System configuration
CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FILE_SYSTEM=y
CONFIG_FILE_SYSTEM_LITTLEFS=y

# SPI NOR configuration
CONFIG_SPI=y
CONFIG_SPI_NOR=y
CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096

# Partition Manager Setttings
CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n
CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y
CONFIG_PM_PARTITION_SIZE_LITTLEFS=0x2000000

If you could please provide specific answers in these 6 questions numbered above it would be extremely helpful.

Thank you very much and I look forward to hearing from you!

Best regards,

Stavros

RE: Mount LittleFS to both internal & external flash

Sigurd — Mon, 30 Oct 2023 12:38:40 GMT

Hi Stavros!

I have taken over the case from Håkon.

Could you try setting CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y ?

Also see this post: Unable to use LittleFS on External Flash on nrf9160

RE: Mount LittleFS to both internal & external flash

clockis — Tue, 24 Oct 2023 13:17:26 GMT

Greetings,

A kind reminder for any updates on my previous questions, if you require more information to answer these questions I'd be more than willing to provide it so this issue can be resolved.

I look forward to hearing from you.

Best Regards,

Stavros F.

RE: Mount LittleFS to both internal & external flash

clockis — Wed, 18 Oct 2023 11:26:58 GMT

Hi,

Kind reminder on any update or any info on this! If any other information is needed please inform me and I will provide it!

Thank you and I look forward to hearing from you

RE: Mount LittleFS to both internal & external flash

clockis — Tue, 10 Oct 2023 10:00:48 GMT

Hello

Kind reminder for any updates or info on this, I have provided as much code, files, logs, and details as I could but if anything else is needed please feel free to ask and I will provide it

Stavros

RE: Mount LittleFS to both internal & external flash

clockis — Thu, 05 Oct 2023 12:55:44 GMT

[quote userid="73166" url="~/f/nordic-q-a/104260/mount-littlefs-to-both-internal-external-flash/448993"]The little FS sample shows how to manually define the mount point. You can include logs and error codes preferably. Give as detailed information as possible.[/quote]

I have already done the manual definition exactly as it is done in the sample (copied the code from the LittleFS sample) as shown in the 1st implementation in my original post, it doesn't work for two instances of the LittleFS because it mounts them on the same mount point of the internal flash memory..

I want to mount one instance of the LittleFS in the internal memory (as it currently is) and one other instance of the LittleFS simultaneously on the external flash IC W25Q512NW.

The first instance is mounted correctly and works as intended (by following the LittleFS sample) but when I try to add the second instance of the LittleFS to the external flash memory IC as shown below, and in every other combination as shown in the original post, it always mounts the second instance to the internal memory as well.

I have also included the logs and the error codes, but I will do that again if it helps.

Manual definition of the mount point in the code:

FS_LITTLEFS_DECLARE_DEFAULT_CONFIG(_LfsConfig);
static struct fs_mount_t lfs_storage_mnt = {
  .type = FS_LITTLEFS,
  .fs_data = &_LfsConfig,
  // .storage_dev = (void *)DT_FLASH_AREA_STORAGE_ID,
  .storage_dev = (void *)FLASH_AREA_ID(littlefs_storage),
  .mnt_point = "/lfs2"
};

struct fs_mount_t *mp = &lfs_storage_mnt;

.DTS file

/ {
	chosen {
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
		zephyr,code-partition = &slot0_partition;
		nordic,pm-ext-flash = &w25q512nw;
	};

&spi1{
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = < &gpio0 26 GPIO_ACTIVE_LOW >;

	w25q512nw: w25q512nw@0 {
		compatible = "jedec,spi-nor";
		status = "okay";
		label = "W25Q512NW";
		wp-gpios = <&gpio0 30 GPIO_ACTIVE_LOW>;
		hold-gpios = <&gpio0 14 GPIO_ACTIVE_LOW>;
		reg = < 0 >;
		spi-max-frequency = < 8000000 >;
		jedec-id = [ ef 60 20 ]; // Manufacturer ID = EFh, Memory Type (ID15-ID8) = 60h and Capacity (ID7-ID0) = 20h 
		size = < 536870912 >;    // Flash capacity in bits = 512M-bit = 1024 * 1024 * 512 * 1bit = 536870912 bit
		has-dpd;
		t-enter-dpd = < 3000 >;  // in nanoseconds - The power-down state will entered within the time duration of tDP: 3us 
		t-exit-dpd = < 30000 >;  // in nanoseconds - The Release from power-down will take the time duration of tRES1: 30us
	};
};

I also tried with this alternative .DTS file

/ {

	chosen {

		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
		zephyr,code-partition = &slot0_partition;
		nordic,pm-ext-flash = &w25q512nw;
	};
};

&spi1{
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = < &gpio0 26 GPIO_ACTIVE_LOW >;

	w25q512nw: w25q512nw@0 {
		compatible = "jedec,spi-nor";
		status = "okay";
		label = "W25Q512NW";
		wp-gpios = <&gpio0 30 GPIO_ACTIVE_LOW>;
		hold-gpios = <&gpio0 14 GPIO_ACTIVE_LOW>;
		reg = < 0 >;
		spi-max-frequency = < 8000000 >;
		jedec-id = [ ef 60 20 ]; // Manufacturer ID = EFh, Memory Type (ID15-ID8) = 60h and Capacity (ID7-ID0) = 20h 
		size = < 536870912 >;    // Flash capacity in bits = 512M-bit = 1024 * 1024 * 512 * 1bit = 536870912 bit
		has-dpd;
		t-enter-dpd = < 3000 >;  // in nanoseconds - The power-down state will entered within the time duration of tDP: 3us 
		t-exit-dpd = < 30000 >;  // in nanoseconds - The Release from power-down will take the time duration of tRES1: 30us
		partitions {
			compatible = "fixed-partitions";
			#address-cells = <1>;
			#size-cells = <1>;
			/* 64 MB partition to use for LFS filesystem */
			ext_storage_partition: partition@0000000 {
				label = "littlefs_storage";
				reg = <0x0000000 0x2000000>;
			};
		};
	};
};

also in the prj.conf is the following

# Flash File System configuration
CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FILE_SYSTEM=y
CONFIG_FILE_SYSTEM_LITTLEFS=y

# SPI NOR configuration
CONFIG_SPI=y
CONFIG_SPI_NOR=y
CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096

# Partition Manager Setttings
CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n

Finally, the error codes/logs are the same as in the original post.

[00:00:00.002,502] <inf> littlefs: littlefs partition at /lfs1
[00:00:00.002,532] <inf> littlefs: LittleFS version 2.4, disk version 2.0
[00:00:00.002,777] <inf> littlefs: FS at flash-controller@4001e000:0xf8000 is 6 0x1000-byte blocks with 512 cycle
[00:00:00.002,777] <inf> littlefs: sizes: rd 16 ; pr 16 ; ca 64 ; la 32
[00:00:00.002,868] <err> littlefs: WEST_TOPDIR/modules/fs/littlefs/lfs.c:1077: Corrupted dir pair at {0x0, 0x1}
[00:00:00.002,899] <wrn> littlefs: can't mount (LFS -84); formatting
[00:00:00.175,292] <inf> littlefs: /lfs1 mounted
[00:00:00.175,292] <inf> littlefs: Automount /lfs1 succeeded
[00:00:00.175,323] <inf> littlefs: littlefs partition at /lfs2
[00:00:00.175,323] <inf> littlefs: LittleFS version 2.4, disk version 2.0
[00:00:00.175,567] <inf> littlefs: FS at flash-controller@4001e000:0xf8000 is 6 0x1000-byte blocks with 512 cycle
[00:00:00.175,598] <inf> littlefs: sizes: rd 16 ; pr 16 ; ca 64 ; la 32
[00:00:00.175,842] <inf> littlefs: /lfs2 mounted
[00:00:00.175,872] <inf> littlefs: Automount /lfs2 succeeded

Could you tell me if anything is wrong in my manual definition of the mount point or in the DTS files? or if something else is causing this behavior? how can I do this so the two instances of the LittleFS can be mounted simultaneously (one for the internal flash) and on for the external flash IC)?

Are the values passed in the members of the struct in the manual definition of the mount point in the code, correct? Do I need to change something there? the LittleFS sample code does not take into account two simultaneous instances so that is why I am asking for verification on this and it seems that there are only two possible permitted values for the .storage_dev member of the struct, and they both point to the internal flash, so I want to know how to populate these members in my case because I either get build errors or the behavior posted above.

Thank you for your feedback, please contact me if any more information is needed.

RE: Mount LittleFS to both internal & external flash

Hakon — Thu, 05 Oct 2023 11:48:49 GMT

[quote user="clockis"]Also, I have scoured every piece of documentation and info on this so I have already seen the samples and have already tried all code from the LittleFS samples[/quote]

Can you give some more information why this is not working for you? The little FS sample shows how to manually define the mount point. You can include logs and error codes preferably. Give as detailed information as possible.

RE: Mount LittleFS to both internal & external flash

clockis — Tue, 03 Oct 2023 12:42:49 GMT

As clearly shown in my original post I have tried both methods of declaring an FSTAB entry and defining the mount point by hand but the results are the same.

So is it possible to have two LittleFS instances in the context of nRF Connect SDK?

It seems that the LittleFS has specific mount point names/predefined partitions that it relates to and does not permit mounting it to a partition with a different label (in the .dts) how can this be done. How can I mount the second instance of LittleFS to a not predefined partition?? Is there a way to define the second partition of my external flash in any other way.

Also, I have scoured every piece of documentation and info on this so I have already seen the samples and have already tried all code from the LittleFS samples, other tickets on DevZone, third party implementation on the net and everything nd anything that is relevant with this that is out there.

Could you provide explicit code on how to define the mount points by hand, in detail, because at this point I have already tried every way and every sub combinations of the way.

Thank you

RE: Mount LittleFS to both internal & external flash

Hakon — Tue, 03 Oct 2023 11:05:48 GMT

They commented;

...the user may not be able to use the FS_FSTAB_ENTRY macro to mount the partition as this thing can only mount to the one of predefined partitions known by the partition manager.

Instead user will have to define the fs_mount_t point by hand, like for example in samples/subsys/fs/littlefs/src/main.c.

RE: Mount LittleFS to both internal & external flash

Hakon — Mon, 02 Oct 2023 09:03:28 GMT

Hello,

I will ask about this internally, and hopefully reply by tomorrow.