Kernel hangs in booting when CONFIG_FSL_OTP enabled in iMx6ULL

[saumil]

I have iMx6ull based custom board.

When CONFIG_FSL_OTP is disabled, it works fine and kernel is loaded successfully.

When CONFIG_FSL_OTP is enabled, kernel gets hang in boot and I am not able to get when it is getting hanged.

Is there any hardware issue or is it configuration issue?

How can I take logs when kernel has not loaded properly to add more information here?

Any help will be appreciated!

[AldoG]

Hello,

I don't know which kernel version you are working with, but please note that OTP driver is not supported anymore in latest releases, it was moved to NVMEM framework.

https://source.codeaurora.org/external/imx/linux-imx/tree/Documentation/driver-api/nvmem.rst?h=imx_5...

Best regards,
Aldo.

[saumil]

Thanks NXP TechSupport for your reply.

My kernel version is 4.19.35-1.1.0+g0f9917c56d59.

I am using FSL_OTP for mac address flashing of ethernet ports.

I have seen behaviour that when I enable them, temperature, cpufreq related files are not present in sysfs.

I will like to know more about NVMEM framework and how it can fullfil my requirements.

Please explain in detail or share document if available.

thank you

[AldoG · Accepted solution]

Hello,

You may check the kernel documentation I have already shared for more information of NVMEM. The 4.14 and later kernel only supports reads through the NVMEM driver.

For blowing fuses one could use the U-Boot fuse command it is capable of reading and writing the efuses.

=> fuse
fuse - Fuse sub-system

Usage:
fuse read <bank> <word> [<cnt>] - read 1 or 'cnt' fuse words,
    starting at 'word'
fuse sense <bank> <word> [<cnt>] - sense 1 or 'cnt' fuse words,
    starting at 'word'
fuse prog [-y] <bank> <word> <hexval> [<hexval>...] - program 1 or
    several fuse words, starting at 'word' (PERMANENT)
fuse override <bank> <word> <hexval> [<hexval>...] - override 1 or
    several fuse words, starting at 'word'

Best regards,
Aldo.