Support for itco v2.

[Mathieu Alexandre-Tétreault]

Hello,

I am currently adding the support for itco v2 to efibootguard (lynx point).
At this point everything seems to be working except the no reboot flag.

My workflow goes as follow:

I boot using efibootguard then load a linux kernel compiled with the
watchdog disabled.
This way I know for sure that the watchdog should reboot the platform
within the delay set
by efibootguard.

What is currently happening is that the watchdog doesn't reboot the
platform but hangs it instead.

I am pretty confident that the issue is the PMC_NO_REBOOT is not set
correctly.
The code that changes the NO_REBOOT_FLAG goest as follow:
https://github.com/siemens/efibootguard/blob/master/drivers/watchdog/itco.c#L117

I already changed the PMC_NO_REBOOT to 0x20 (1 << 5). The here are the
variable that can be wrong PMCBASE_REG, PMCBASE_ADDRMASK and PMC_REG.
I tried matching those register with the information in the linux kernel
but I didn't find the information required.

Would anyone be able to point me in the right direction for this?

Thank you,

Mathieu

[Jan Kiszka]

If I understand the kernel driver correctly, bit 5 is iTCO v2, bit 4 is v3. So
we are actually carrying v3 enablement in EBG. Maybe there is more, just started
to read the code again /wrt v2/v3. What I found so far:

"The iTCO v1 and v2's internal timer is stored as ticks which decrement
every 0.6 seconds. v3's internal timer is stored as seconds (some
datasheets incorrectly state 0.6 seconds)."

But that should only give us a moderately different timeout.

Did you check if the Linux driver works correctly on your platform? Then it
might be worth comparing register contents carefully again, what does Linux
write to where compared to what EBG does.

Jan

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