Re: Boot hang on Origen with (!SMP && CPU_IDLE)

[Arnd Bergmann <arnd@arndb.de>]

On Monday 06 January 2014, Tushar Behera wrote:
> The device tree node for l2x0 device was missing. After adding a node
> as below I can start booting Origen board.
> 
> diff --git a/arch/arm/boot/dts/exynos4210-origen.dts
> b/arch/arm/boot/dts/exynos4210-origen.dts
> index 1a12fb2..675f323 100644
> --- a/arch/arm/boot/dts/exynos4210-origen.dts
> +++ b/arch/arm/boot/dts/exynos4210-origen.dts
> @@ -32,6 +32,13 @@
> 
> +       l2-cache-controller@10502000 {
> +               compatible = "arm,pl310-cache";
> +               reg = <0x10502000 0x1000>;
> +               cache-unified;
> +               cache-level = <2>;
> +       };
> +

Ok, very good!

> >> be a good time to get rid of the L2_AUX_VAL and L2_AUX_MASK defines and
> >> just read the respective settings from DT.
> 
> Ok.

Does the node you list above have the right settings for this?

> > 2) There is no L2 cache controller node in Exynos4*.dtsi.
> >
> > It should be added, but L2 cache can't be enabled on all boards yet,
> > since on boards where secure firmware is enabled, special configuration
> > involving SMC calls is required. Patches for this are queued on my work
> > queue, but it's quite tricky due to 1), which needs to consider whether
> > secure firmware is enabled or not.
> >
> 
> In that case, would it be ok to add the node for Origen board only?

Wouldn't that leave other systems still broken? I'm particularly worried
about what patch to backport to linux-stable. We should definitely add
the node for Origen, but we may also have to revert my broken patch
in all affected kernel versions.

Are there any systems that may or may not have secure firmware enabled
depending on the boot loader, or do we always know whether secure firmware
is there or not?

	Arnd