How do I get the reset cause with nRF Connect SDK?

[MaLu]

Hi,

I am using an nRF9160/nRFConnect SDK 1.8.0/VSCode and my application uses MCUBoot and SPM. It is a "non secure" application.

I am trying to get a reset cause. 

hwinfo_get_reset_cause() just leads to a weak function that always returns -ENOSYS (= -1).

In my prj.conf I have enabled CONFIG_HWINFO=y, for this purpose. 

CONFIG_HWINFO_NRF=y outputs this warning: HWINFO_NRF (defined at drivers/hwinfo/Kconfig:31) was assigned the value 'y' but got the
value 'n'. Check these unsatisfied dependencies: (!TRUSTED_EXECUTION_NONSECURE).

 

I am kind of new to this whole secure/non-secure thing, so I am probably missing something fundamentally in this regard, so help to get the reset cause would be appreciated.

Thanks!

[Hakon]

Hello,

I believe you can read out the value of the RESETREAS register to get the reset reason.

[MaLu]

Hi,
I've read that as well, but was hoping for a more Zephyr-ish approach.

[Hakon]

MaLu said:

I've read that as well, but was hoping for a more Zephyr-ish approach.

I'm not sure what you mean by this, but if you don't want to read the register directly you can use the nrf power library function

nrf_power_resetreas_get(NRF_POWER_NS);

[MaLu]

Thank you.

This is already much better, than just reading out the register.
I am sorry, that I'm not explaining myself very well. 
When I say Zephyr-ish approach, I mean, that I want to be as Hardware-agnostic in my code as possible. With nrf_power_resetreas_get(NRF_POWER_NS) and espeacially with just reading from the register, I am dependent on the Hardware. So far I have managed to only use very high level functions with my code and was hoping to also be able to do this for the reset cause. That's why I was hoping to make hwinfo_get_reset_cause() work, since it is not nrf specific and would only use the underlying nrf driver. 
I have noticed, that there is hwinfo_nrf stuff (hwinfo_nrf.c), but I cannot figure out, how to get the hwinfo wrapper to use that driver in my constellation.

[Hakon]

The hwinfo driver you are referring to is most likely outdated, as it is reading the register from the secure domain. The driver does not have a non-secure implementation as far as I can tell.

It calls nrf_power_resetreas_get() with the argument NRF_POWER instead of NRF_POWER_NS;

nrf_power_resetreas_get(NRF_POWER);

If you want something "hardware-agnostic", my suggestion is you register a feature request in the Zephyr project.

[MaLu]

Thank you very much for researching this, it is much appreciated!