LittleFS failing to mount on QSPI NOR Flash (err -28)

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Przemek Ostrowski — Thu, 01 May 2025 12:09:12 GMT

I found this in the datasheet:
"The W25Q01JV device is a two 512M-bit stack die that supports linear addressing for the full 1G-bit memory address range."

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Przemek Ostrowski — Thu, 01 May 2025 11:34:13 GMT

Brett_G Thank you for quick response!

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Wed, 30 Apr 2025 18:28:04 GMT

Its been a while since I've had to think on this, so my memory is a bit stale, but I did not have implement anything extra for die switching within the w25q01. With the proper configuration, you should be able to access all 128MB.

My use case did not involve loading firmware onto external flash so unfortunately I cannot speak to its compatibility with mcuboot.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Przemek Ostrowski — Wed, 30 Apr 2025 16:26:28 GMT

We are considering using w25q01jvzeim (1Gbit) or w25q01jvzeiq (1Gbit) . These are dual die 2x512Mbit.
1. Does the QSPI driver handle the die switching?
2. If not than what would I have to do in order to be able to use all 128 MB of storage?
3. Is this memory w25q01j compatible with mcuboot on nrf5340 (Brett_G did you successfully updated firmware using the external memory)?

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Thu, 02 May 2024 15:31:46 GMT

Integration into my main application is going well. I want to round off this thread with some of the config settings I've found to have made a difference, and others I've settled on. Just in case someone finds it helpful.

My relevant device tree came out to be this:

&qspi {
	status = "okay";
	pinctrl-0 = <&qspi_default>;
	pinctrl-1 = <&qspi_sleep>;
	pinctrl-names = "default", "sleep";
    w25q01: w25q01@0 {
        compatible = "nordic,qspi-nor";
		reg = <0>;
		writeoc = "pp4o";
		readoc = "read4io";
		sck-frequency = <16000000>;
		jedec-id = [EF 40 21];
        //sfdp-bfp = [
        //e5 20 fb ff  ff ff ff 3f  44 eb 08 6b  08 3b 42 bb
        //fe ff ff ff  ff ff 00 00  ff ff 40 eb  0c 20 0f 52
        //10 d8 00 00  36 02 a6 00  82 ea 14 e2  e9 63 76 33
        //7a 75 7a 75  f7 a2 d5 5c  19 f7 4d ff  e9 70 f9 a5
        //];

		size = <1073741824>;
		has-dpd;
		t-enter-dpd = <3000>;
		t-exit-dpd = <3000>;
        //requires-ulbpr;
        sck-delay = <5>;
        quad-enable-requirements= "S2B1v1";
        address-size-32;
        enter-4byte-addr= <0xB7>; // 0xA5 is what is reported, but DS says 0xB7?
	};
};

I found that the sdfp-bfp field, and a few others from the JESD216 example weren't exactly accurate for some reason. But the manual config above seemed to work well. Also having nordic,drive-mode = <NRF_DRIVE_H0H1>; in my qspi pinctrl proved necessary.

Since I'm using the partition manager, and FSTAB or partition setting in the DTS would not have any effect, instead I could either manually declare it in pm_static, or use the prj.conf settings to put it in external and set the size. I chose the latter, with this code configuration to set the mount point:

FS_LITTLEFS_DECLARE_DEFAULT_CONFIG(lfs_storage);
static struct fs_mount_t lfs_storage_mnt = {
	.type = FS_LITTLEFS,
	.fs_data = &lfs_storage,
	.storage_dev = (void *)FIXED_PARTITION_ID(littlefs_storage),
	.mnt_point = "/lfs",
};

My current prf.conf settings regarding qspi and FS are:

# file system
CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FILE_SYSTEM=y
CONFIG_DISK_ACCESS=y
CONFIG_FILE_SYSTEM_MKFS=y
CONFIG_FILE_SYSTEM_LITTLEFS=y

# nvs and partitioning
CONFIG_NVS=y
CONFIG_SETTINGS=y
CONFIG_SETTINGS_NVS=y
CONFIG_NORDIC_QSPI_NOR=y
CONFIG_NORDIC_QSPI_NOR_FLASH_LAYOUT_PAGE_SIZE=65536
CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y
CONFIG_PM_PARTITION_SIZE_LITTLEFS=0x8000000
CONFIG_MPU_ALLOW_FLASH_WRITE=y
CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n

Obviously having pullups on CS, IO3/HOLD and IO2/WP was the main difference maker in getting it working, but wanted to cover the other lessens learned.

I had already begun the process to update to 2.6.X, just to stay up to date, but it is good to hear that a possible fix has already been rolled out.

- Brett

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Sigurd Hellesvik — Thu, 02 May 2024 14:48:47 GMT

Great find!

This seems similar to the issue in spi_flash is not running on nRF5340DK out of box We first found this for v2.6.0, so I thought this would not be an issue for you since you use v2.4.2.

But one of the PRs I mention there also mention IO3, so it is a good chance that this will have been fixed for you in v2.6.1.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Thu, 02 May 2024 14:06:20 GMT

I believe I found the issue, I was able to get the littlefs sample working after adding a pullup resistor to both IO3/HOLD and IO2/WP. I wrongfully was assuming that the driver would be driving those high/low when needed, and that running it in Quad enable that it wouldn't be needed at all.

Odd that the flash and JESD216 samples worked with this hardware configuration, while the littlefs sample could not.

I will continue with these new hardware and firmware configurations in adding it into my main application, and update if I run into any other issues, otherwise I'll mark it closed.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Wed, 01 May 2024 16:33:12 GMT

As an extra sanity check, I went ahead and ran the littlefs example with nothing changed, except the boards file to have the W25Q01JV instead of the MX25R64. The output was pretty much the same:

I: littlefs partition at /lfs1
I: LittleFS version 2.5, disk version 2.0
I: FS at w25q01@0:0x0 is 2048 0x10000-byte blocks with 512 cycle
I: sizes: rd 16 ; pr 16 ; ca 64 ; la 32
E: WEST_TOPDIR/modules/fs/littlefs/lfs.c:1234: Corrupted dir pair at {0x0, 0x1}
W: can't mount (LFS -84); formatting
W: WEST_TOPDIR/modules/fs/littlefs/lfs.c:1897: Superblock 0x0 has become unwritable
E: format failed (LFS -28)
E: fs mount error (-28)
E: Automount /lfs1 failed: -28
*** Booting nRF Connect SDK d96769faceca ***
Sample program to r/w files on littlefs
Area 0 at 0x0 on w25q01@0 for 134217728 bytes
/lfs1 automounted
E: mount point not found!!
FAIL: statvfs: -2
E: fs not mounted (mp == 0x20000054)
/lfs1 unmount: -22

The example does not even use the Partition manager, so I dont think it is the cause of these issues.

One odd thing I am noticing, with the flash size declared in bits using size = <1073741824>; the device tree visualizer shows the whole flash as 1GByte instead of 1Gbit. But the partition size is correct.

If I try to use size-in-bytes = <134217728>; it shows 0B for flash area on the sample, with the same error output when ran. Meanwhile it wont even compile with size-in-bytes used at all in my main application.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Tue, 30 Apr 2024 12:16:46 GMT

With NVM and Settings disabled, I still get the same (err -28). I do use the Partition manager and have confirmed that CONFIG_PARTITION_MANAGER_ENABLED is set.

I have a pm_static.yml defined as below:

mcuboot:
  address: 0x0
  end_address: 0x10000
  region: flash_primary
  size: 0x10000
mcuboot_primary:
  address: 0x10000
  end_address: 0x64000
  orig_span: &id001
  - mcuboot_pad
  - app
  region: flash_primary
  size: 0x54000
  span: *id001
mcuboot_pad:
  address: 0x10000
  end_address: 0x10200
  region: flash_primary
  size: 0x200
app:
  address: 0x10200
  end_address: 0x64000
  region: flash_primary
  size: 0x53E00
mcuboot_primary_app:
  address: 0x10200
  end_address: 0x64000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x53E00
  span: *id002
mcuboot_secondary:
  address: 0x64000
  end_address: 0xB8000
  region: flash_primary
  size: 0x54000
mcuboot_secondary_1:
  address: 0xB8000
  end_address: 0xF8000
  region: flash_primary
  size: 0x40000
settings_storage:
  address: 0xF8000
  end_address: 0xFC000
  region: flash_primary
  size: 0x4000
user_storage:
  address: 0xFC000
  end_address: 0x100000
  region: flash_primary
  size: 0x4000

otp:
  address: 0xff8100
  end_address: 0xff83fc
  region: otp
  size: 0x2fc

pcd_sram:
  address: 0x20000000
  end_address: 0x20002000
  region: sram_primary
  size: 0x2000
sram_primary:
  address: 0x20002000
  end_address: 0x20070000
  region: sram_primary
  size: 0x6e000
rpmsg_nrf53_sram:
  address: 0x20070000
  end_address: 0x20080000
  placement:
    before:
    - end
  region: sram_primary
  size: 0x10000

mcuboot_primary_1:
  address: 0x0
  size: 0x40000
  device: flash_ctrl
  region: ram_flash
ram_flash:
  address: 0x40000
  end_address: 0x40000
  region: ram_flash
  size: 0x0

lfs_part:
  address: 0x0
  end_address: 0x8000000
  device: w25q01
  region: external_flash
  size: 0x8000000

The last entry in pm_static, is where I have tried to statically define the lfs partition on external flash. I have tried with and without this static config, as well as with and without

CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y.

It is worth noting for my use case that I would like to have NVS on internal flash while having LittleFS on external flash. But for the sake of figuring out the issue, we can have NVS disabled for now.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Sigurd Hellesvik — Tue, 30 Apr 2024 08:14:40 GMT

Good to know that that sample works.

Next up, lets look at partitioning.

NVS and settings will do partitioning stuff. Can you test littlefs without those and see if that works?

Do you use the partition manager in your code or not?
To check this, see if CONFIG_PARTITION_MANAGER_ENABLED is set.
See this course for an intro to the Partition Manager.

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Brett_G — Mon, 29 Apr 2024 14:02:41 GMT

Hi Sigurd,
I ran the example for multiple sectors, and the output looks to be good:

So If the QSPI flash seems to be working properly, I'd assume the filesystem or partitioning configuration is probably at fault.

Any ideas for what to change in the configuration?

- Brett

RE: LittleFS failing to mount on QSPI NOR Flash (err -28)

Sigurd Hellesvik — Mon, 29 Apr 2024 11:17:50 GMT

Hi,

Could you also test the SPI Flash sample? (It is configured for QSPI for the nRF5340)

It would be interesting to see if you see the same error without a filesystem.

Regards,
Sigurd Hellesvik