Alexander Aring <alex.aring@gmail.com> writes:

> On Mon, Dec 21, 2015 at 03:07:44PM -0800, Eric Anholt wrote:
> ...
>> >
>> > But still getting this panic, your patches does not contain some
>> > defconfig, so I still try to figure out what I need to enable to get it
>> > working. Maybe it is some missing config entry which should be enabled.
>> >
>> > But, for me it looks like some devicetree issue, because of_iomem returns
>> > NULL, at [0]. Don't know what I am doing wrong.
>> 
>> My best guess is that since you're not using U-Boot, the firmware's
>> mangling the DT in some way that breaks us.  Notably, in my current
>> firmware checkout, set /soc/ranges to just the first entry that we're
>> using, which would break the mapping.  However,
>> rpi/rpi-4.4.y:arch/arm/boot/dts/bcm2709.dtsi uses the same /soc/ranges
>> setup that we do, so I'm not sure what's going on.  Perhaps
>> bcm2709_io_desc[]'s initialization covers for it?
>
> I boot here with two different bootloaders, both ends in the same panic.
>
> Finally I figured out if I do a user/kernel split (2G/2G) then the
> issue is gone.

Huh.  Not sure what's going on there.

> Later I need to enable "CONFIG_HAVE_ARM_ARCH_TIMER" so the kernel
> doesn't hang forever.

I'll add a dependency for that -- we definitely want the arch timer.  I
would have thought that the 2835 timer would still be able to make
things work, though.

> After finally booting the RPi2 I get several messages of:
>
> unexpected IRQ trap at vector 00
>
> while typing _one_ character over uart.

We were doing some debugging of that recently.  It seems that every once
in a while we get woken up but nothing shows up in the top-level status
register.  We need to just make the irqchip ignore instead of trying to
look up a handler in that case, but I haven't prioritized it because it
makes me worry that I'm just papering over a problem in our IRQ masking
or something.

I haven't seen any problems other than the printk, though.

> Can you provide somehow your RPi2 kernelconfig?

http://people.freedesktop.org/~anholt/dotconfig-bcm2836-2015-12-22.txt