A20-SOM wake up from NMI_N

[Paul Morrison]

I am making some testing over A20-SOM. I have a signal connected to NMI_N pin and with a legacy distribution, with power_start=0 on FEX, I am able to poweroff the board from command line (while the board is still powered) and then poweron/weakup the board raising up the signal on NMI_N.

However, I need to do this on an armbian mainline distribution. I poweroff the board from command line (but keep the board powered), the PWR_LED keeps turn on and the board should wakeup when I turn on the signal on NMI_N and it does on my legacy distribution but not in armbian.

Has anyone any clue, advice/tip to make this work in armbian?


Many thanks for considering my request!

[JohnS]

Worth asking in an armbian place.

BTW, if it's NMI_N I would have expected you'd keep it high but pull it low to activate it.

John

[Paul Morrison]

I asked on armbian forum and this is their answer:

https://forum.armbian.com/topic/7481-a20-som-wake-up-from-nmi_n/

the problem is "already implemented in the legacy/BSP stack. Since mainline u-boot and kernel were made from scratch rather than by porting the Allwinner code, this functionality and many other things were not added."

so now im looking how can I implement this on mainline, but really does not know where to start.

Any alternative to wake up from suspend/hibernate would be usefull as well.

[JohnS]

Oh, that's a bit disappointing.

Maybe try linux-sunxi.org - check whether it's intended to be done on their site first then consider their ML.

Perhaps also the U-boot ML if it is indeed sitting in U-boot.

hmm... actually you probably do need to know where it is when shut down (U-boot or some kernel loop).  (Reading code will show this.)

Someone may have useful suggestions or you may even be able to pay someone in the project(s) to do it.

John