AM3352: Reason for last reboot

Abdul Hameed Syed

Part Number: AM3352

Hello Support,

I'm working on a requirement that says, we need to know the reason for previous reboot.

Previous reboot could be either a graceful shutdown or an ungraceful termination. If it is an ungraceful termination, we want to know what has caused the ungraceful termination.

I'm trying to use linux's 'last' utility. But all I get here is, if the termination is graceful or ungraceful.

Are there any registers set or reset that would get me previous ungraceful termination information.

Are there any utilities that would help in achieving this???

Thanks and regards,
Hameed.
e = syedabdul.hameed2@carrier.com

over 5 years ago

0 Andreas Dannenberg over 5 years ago

TI__Guru 69977 points

Hi Abdul,

you could manually read the device's PRM_RSTST register, it'll give you information regarding the source of reset (external, watchdog, warm, or cold), see AM335x TRM for more detail.

This register however doesn't seem to be readily exposed through a Kernel driver, so you would need to extend an existing driver (such as the WDT driver) or add a new driver to the Kernel to do that. Or, read the register from userspace via devmem (not a great idea really but workable in certain scenarios).

Also see here: https://e2e.ti.com/support/processors/f/791/t/419216

Might also be helpful to generally google for PRM_RSTST to see what others have come up with.

Regards, Andreas

0 Abdul Hameed Syed over 5 years ago in reply to Andreas Dannenberg

Prodigy 30 points

Hello Andreas,

Thanks a lot for the valuable insight.

I prefer user space implementation.

Thanks again and regards,
Hameed.

0 Andreas Dannenberg over 5 years ago in reply to Abdul Hameed Syed

TI__Guru 69977 points

Hi Hameed,

if you want to access the register via userspace, this post here has a some info on how to do that:

https://e2e.ti.com/support/processors/f/791/p/419216/1775300#1775300

Can you please check the "devmem" command mentioned there. Actually, you probably need to instead use either "devmem2" or the "omapconf" tool using our current SDK but the basic principle is the same. Let me know if you have any issues.

Regards, Andreas

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AM3352: Reason for last reboot