reboot fails on at91sam9g20 with kernel 4.x

reboot fails on at91sam9g20 with kernel 4.x

[Alexander Dahl]

Hei hei,

while upgrading a at91sam9g20 based board to a recent kernel I stumbled 
over a problem I can not solve by myself. We have a board which is more 
or less a stripped down version of the at91sam9g20ek. The kernels I was 
trying lately with a custom DT were 3.14.79, 3.18.44 (didn't work), 
4.4.32, 4.8.6 and 4.9-rc6+. The rootfs is built with 
OSELAS.Toolchain-2014.12.2, ptxdist 2016.11.0, gcc 4.9.2, glibc 2.20, 
busybox v1.24.2 and it's on a UBIFS on NAND flash.

The following happens if I try to reboot a 4.x kernel from console:

	The system is going down NOW!
	Sent SIGTERM to all processes
	macb fffc4000.ethernet eth0: link down
	Requesting system reboot
	reboot: Restarting system
	Reboot failed -- System halted

The last message obviously comes from arch/arm/kernel/reboot.c and 
something fails. ;-)

Searching the web I found someone having a similar problem here:

	https://groups.google.com/forum/#!topic/acmesystems/vC_66zmcatk

Reboot works with 3.x kernels (if they run at all). I'll try a 4.1 
tomorrow, but I would be happy if someone could assist me in debugging 
this.

Greets
Alex

reboot fails on at91sam9g20 with kernel 4.x

[Alexandre Belloni]

Hi,

On 23/11/2016 at 17:13:05 +0100, Alexander Dahl wrote :
> The last message obviously comes from arch/arm/kernel/reboot.c and 
> something fails. ;-)
> 
> Searching the web I found someone having a similar problem here:
> 
> 	https://groups.google.com/forum/#!topic/acmesystems/vC_66zmcatk
> 
> Reboot works with 3.x kernels (if they run at all). I'll try a 4.1 
> tomorrow, but I would be happy if someone could assist me in debugging 
> this.
> 

Since 3.18, the shdwc and reset controller have their own drivers that
may or may not be compiled in the kernel. Can you check you have
CONFIG_POWER_RESET_AT91_POWEROFF and CONFIG_POWER_RESET_AT91_RESET set
in your configuration? Also, you probably want to check the DT definition
of the shdwc and the rstc.

Regards,

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

reboot fails on at91sam9g20 with kernel 4.x

[Alexander Dahl]

Hei hei,

Am Mittwoch, 23. November 2016, 23:11:21 schrieb Alexandre Belloni:
> Since 3.18, the shdwc and reset controller have their own drivers that
> may or may not be compiled in the kernel. Can you check you have
> CONFIG_POWER_RESET_AT91_POWEROFF and CONFIG_POWER_RESET_AT91_RESET
> set in your configuration? Also, you probably want to check the DT
> definition of the shdwc and the rstc.

You were right, those were not set.

-# CONFIG_POWER_RESET is not set
+CONFIG_POWER_RESET=y
+CONFIG_POWER_RESET_AT91_POWEROFF=y
+CONFIG_POWER_RESET_AT91_RESET=y

With the above change in the kernel config the board reboots fine.

I'm not quite sure anymore how I got to my kernelconfig, maybe based on 
a pre 3.18 config without going through oldconfig. 

I double checked the at91_dt_defconfig from 4.8.10 now and it activates 
those options, maybe I should have done this in the first place.

So thank you very much for your hint. :-)

Greets
Alex

-- 
------------------------------------------------------------------------
Thorsis Technologies GmbH                     Tel.: +49-391-544 563-3036
Oststra?e 18                                  Fax.: +49-391-544 563-9099
39114 Magdeburg                                  http://www.thorsis.com/

Sitz der Gesellschaft: Magdeburg
Amtsgericht Stendal HRB 110339
Gesch?ftsf?hrer: Dipl.-Ing. Thorsten Szczepanski
------------------------------------------------------------------------