Re: [PATCH] ARM64: dts: rockchip: add core dtsi file for RK3399 SoCs

[Heiko Stübner]

Am Donnerstag, 21. April 2016, 12:30:18 schrieb Marc Zyngier:
> On Thu, 21 Apr 2016 18:47:20 +0800
> 
> "Huang, Tao" <huangtao@xxxxxxxxxxxxxx> wrote:
> > Hi, Mark:
> > 
> > On 2016å04æ21æ 18:19, Mark Rutland wrote:
> > > On Thu, Apr 21, 2016 at 11:58:12AM +0800, Jianqun Xu wrote:
> > >> +		cpu_l0: cpu@0 {
> > >> +			device_type = "cpu";
> > >> +			compatible = "arm,cortex-a53", "arm,armv8";
> > >> +			reg = <0x0 0x0>;
> > >> +			enable-method = "psci";
> > >> +			#cooling-cells = <2>; /* min followed by max */
> > >> +			clocks = <&cru ARMCLKL>;
> > >> +		};
> > >> +		cpu_b0: cpu@100 {
> > >> +			device_type = "cpu";
> > >> +			compatible = "arm,cortex-a72", "arm,armv8";
> > >> +			reg = <0x0 0x100>;
> > >> +			enable-method = "psci";
> > >> +			#cooling-cells = <2>; /* min followed by max */
> > >> +			clocks = <&cru ARMCLKB>;
> > >> +		};
> > >> +
> > >> +	arm-pmu {
> > >> +		compatible = "arm,armv8-pmuv3";
> > >> +		interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_LOW>;
> > >> +	};
> > > 
> > > This is wrong, and must go. There should be a separate node for the PMU
> > > of each microarchitecture, with the appropriate compatible string to
> > > represent that (see the juno dts).
> > 
> > You are right. The first version we wrote is:
> >     pmu_a53 {
> >     
> >         compatible = "arm,cortex-a53-pmu";
> >         interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_LOW>;
> >         interrupt-affinity = <&cpu_l0>,
> >         
> >                      <&cpu_l1>,
> >                      <&cpu_l2>,
> >                      <&cpu_l3>;
> >     
> >     };
> >     
> >     pmu_a72 {
> >     
> >         compatible = "arm,cortex-a72-pmu";
> >         interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_LOW>;
> >         interrupt-affinity = <&cpu_b0>,
> >         
> >                      <&cpu_b1>;
> >     
> >     };
> > 
> > but unfortunately, the arm pmu driver do not support PPI in two cluster
> > well,
> > so we have to replace with this implementation.
> > 
> > > In this case things are messier as the same PPI number is being used
> > > across clusters. Marc (Cc'd) has been working on PPI partitions, which
> > > should allow us to support that.
> > 
> > Great! So what we can do right now? Wait this feature, and delete
> > arm-pmu node?
> 
> I'd rather you have a look at the patches, test them with your HW,
> and comment on what doesn't work!

I would think we could do it in two tracks, testing and fixing but also letting 
the rk3399 devicetrees move forward without the pmu at first :-) .

> 
> You can find the patches over there:
> 
> https://lkml.org/lkml/2016/4/11/182
> 
> and on the following branch:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git
> irq/percpu-partition
> 
> Of course, you'll have to hack a bit in the PMU code to make it
> understand per-PMU affinity together with percpu interrupts, but it
> wouldn't be fun if there was nothing to do...
> 
> Thanks,
> 
> 	M.