NRF52840 fs_sample SD fs_close error on NCS 2.7.0

[sheldon_b]

I am getting an fs_close() -5 error (-EIO) when I write to an SD card using fatfs. I determined this error was associated with FR_DISK_ERR in fat_fs.c.

Additional info

• I'm using a custom board.
• I didn't have these problems with NCS 2.5.0
• The contents are actually being written to the card.
• The file closes successfully If I open the file but don't write to it.

DTS

/**
 * The NRF52 documentation states that SPIM0-2 are limited to 8Mbps
 * datarates. SPIM3 is used because its capable of a max throughput
 * of 32 Mbps (32 MHZ).
 */
&spi3 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	pinctrl-0 = <&spi3_default>;
	pinctrl-1 = <&spi3_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = <&gpio1 0 GPIO_ACTIVE_LOW>;
	sdhc0: sdhc@0 {
		compatible = "zephyr,sdhc-spi-slot";
		reg = <0>;
		status = "okay";
		mmc {
			compatible = "zephyr,sdmmc-disk";
			status = "okay";
		};
		spi-max-frequency = <32000000>;
		pwr-gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
	};
};

prj.conf

CONFIG_DISK_ACCESS=y
CONFIG_LOG=y
CONFIG_FILE_SYSTEM=y
CONFIG_FAT_FILESYSTEM_ELM=y
CONFIG_PRINTK=y
CONFIG_MAIN_STACK_SIZE=2048

CONFIG_SPI=y
CONFIG_DISK_DRIVER_SDMMC=y

[Maria Gilje]

Hello,

I have started to investigate this, and I will get back to you tomorrow with my initial findings.

Best regards,

Maria

[Maria Gilje]

Hello,

I was not able to find anything meaningful from my initial investigations. The potential sources for FR_DISK_ERR occuring was many, and I would not be able to conclude anything without debugging this. I would like to reproduce this, but it could be tricky since you are using a custom board.

If you can do a debugging session to find out where FR_DISK_ERR is returned, this will be of much help.

As a side-note: Since this is a Zephyr sample, there could be help to find in the Zephyr project Discord server as well.

Best regards,

Maria

[sheldon_b]

I will try to find more information for you.

[SST]

HI Maria,

I seem to have the same situation:

• Code based on the fs_sample
• Worked on NCS 2.5.0
• Broken after moving to NCS 2.7.0
• Custom board but it is ultimately an sd card on the SPI port.
• fs_open() succeeds
• fs_write() fails with -13 the file is created but the content is not written
• fs_close() fails with -5
• fs_mkdir() also returns an error. The directory is created.

The write process fails on line 4032 of ff.c.

if (!(fp->flag & FA_WRITE)) LEAVE_FF(fs, FR_DENIED);    

fp->flag is 0x58
FA_WRITE is 0x2

flag is set to 0x58 in f_open(), (called by fs_open(&file, path, FS_O_CREATE)). It is set via mode (line 3863) however the steps to this point are optimised out.

Thanks,

Tom

[SST]

Slight progress.

The write is a red herring I introduced while trying to create a simplified test case. (The fs_sample opens with only FS_O_CREATE, adding FS_O_WRITE fixed it).

The close is still, however, failing.

[SST]

I think I have found the issue.

There is a missing break between line 796 and 797 of sd_ops.c. The bug was introduced in this commit:

https://github.com/nrfconnect/sdk-zephyr/commit/05c84ccb2d7a7cb39e49d769503ac22edffeb6f7

Do you do any testing on hardware for release? It seems not. Perhaps you might save your customers a lot of time with something like https://rockface.io/

Thanks,

Tom

[sheldon_b]

Hi Tom,

I really appreciate you picking up the torch here. Excellent work troubleshooting so fast. I'll swap back to this project right now and see if I can replicate the fix.

[sheldon_b]

I just verified the fix works on my hardware as well.