bootcount support for AM62 RTCSS

[Bryan Brattlof]

Hi Thorm!

On April  8, 2025 thus sayeth Thom Nichols:
> I’d like to get bootcount support for the AM62 RTCSS.  The RTCSS on 
> the AM62 is very similar to the AM33.  In fact, I’m pretty sure the 
> bootcount_davinci driver would work for AM62, with just the register 
> address/ offset and KICK_WE constants redefined for the correct AM62 
> values.  A while back I tested the AM62 scratch register from 
> userspace [1] and confirmed it works the same as the AM33.
> 

Wonderful! It is a different IP from the AM335 but not completely 
different however I think your approach should work.

> I’ve never contributed to u-boot but I believe I could get a working 
> PR that modifies the davinci_bootcount driver, if this would be 
> acceptable.
> 

You should feel free to start if you want! U-Boot is very welcoming in 
this regard. The more devs we have in U-Boot the better :)

> Alternately I don’t know if there’s any near-term plan for any of the 
> AM62 maintainers to port the rtc driver so that bootcount/rtc could be 
> used.  I think doing this would be beyond my capabilities.
> 

So we do have some plans to improve RTC support in both in Linux and in 
U-Boot to extend some features needed for the latest Sitara class SoC 
but I'm unsure about timelines. I've added a ticket internally to track 
this if we get to it before you do though :)

~Bryan

> Thanks in advance.
> 
> Thom Nichols
> 
> 1. https://github.com/VoltServer/uboot-bootcount/pull/15/files