On Wed, Oct 09, 2013 at 04:48:32PM -0500, Rob Herring wrote: > On Tue, Oct 8, 2013 at 5:15 PM, Olof Johansson <olof@xxxxxxxxx> wrote: > > [Adding Tony, who reported a mainline booting issue, and Sean who > > helped me track this down] > > > > On Mon, Sep 23, 2013 at 7:15 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > >> On Sat, Sep 21, 2013 at 04:24:59PM +0100, Tomasz Figa wrote: > >>> Hi Yuvaraj, > >>> > >>> On Wednesday 18 of September 2013 15:41:53 Yuvaraj Kumar C D wrote: > >>> > Without the "clock-frequency" property in arch timer node, could able > >>> > to see the below crash dump. > >>> [snip] > >>> > diff --git a/arch/arm/boot/dts/exynos5250.dtsi > >>> > b/arch/arm/boot/dts/exynos5250.dtsi index 7d7cc77..668ce5d 100644 > >>> > --- a/arch/arm/boot/dts/exynos5250.dtsi > >>> > +++ b/arch/arm/boot/dts/exynos5250.dtsi > >>> > @@ -96,6 +96,7 @@ > >>> > <1 14 0xf08>, > >>> > <1 11 0xf08>, > >>> > <1 10 0xf08>; > >>> > + clock-frequency = <24000000>; > >>> > >>> Shouldn't it rather come from some clock provided by some clock controller > >>> instead? > >>> > >>> The frequency would be then retrieved using clk_get_rate() on a clock > >>> received by clk_get(), specified in device tree using generic clock > >>> bindings. > >> > >> If the bootloader has initialised the generic timer correctly, the > >> CNTFRQ register should contain the clock frequency, independent of any > >> external clock. > > > > So, we just sat here to bisect a problem on the Samsung Chromebook > > where we hit exactly this problem. The read-only firmware on the > > device does not set CNTFRQ at boot, so this fails. > > > > Apparantly the u-boot that comes with Arndale sets it, so I haven't > > seen this error on that platform. > > > >> Having the bootloader set CNTFRQ is by far the preferable solution, it > >> is architected for this purpose. > > > > Unfortunately there is now real hardware out there that needs this due > > to firmware bugs / missing features, so there's little other choice. > > :( > > > > I'll pick this patch up in the fixes branch for 3.12, unless someone > > complains loudly. > > Perhaps the subject should say something about this only applying to exynos. Definitely, and I'll add a comment as Mark requested. -Olof -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
