Hi Rob, On 5/6/19 12:29 PM, Lukasz Luba wrote: > Hi Rob, > > On 5/2/19 10:24 PM, Rob Herring wrote: >> On Thu, May 2, 2019 at 3:52 AM Lukasz Luba >> <l.luba@xxxxxxxxxxxxxxxxxxx> wrote: >>> >>> Hi Rob, >>> >>> On 5/1/19 12:36 AM, Rob Herring wrote: >>>> On Fri, Apr 19, 2019 at 03:48:07PM +0200, Lukasz Luba wrote: >>>>> Extend the documenation by events description with new >>>>> 'event-data-type' >>>>> field. Add example how the event might be defined in DT. >>>> >>>> Why do we need event types in DT? We don't do this for other h/w >>>> such as >>>> ARM PMU. >>> In ARM PMU all the events are hard-coded into the driver code i.e. in v7 >>> arch/arm/kernel/perf_event_v7.c >>> and are seen from perf. They are different type and for different >>> purpose. The Ecynos PPMU events are not seen in perf, they are >>> for internal monitoring and must not be reset by other actors like perf. >>> They are used by the 'bus drivers' to made some heuristics and tune the >>> internal settings, like frequency. >>> >>> Chanwoo has written PPMU driver which relies on DT definition. >>> The DT events are used by other DT devices by phandle. >> >> How is that done? I don't see anything in the binding for that. > Here are the DT devices and how they are pinned together: > - declared devfreq events: > https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/exynos4412-ppmu-common.dtsi > > - devfreq events pinned to the bus device: > https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/exynos4412-odroid-common.dtsi#L107 > > - the bus device itself: > https://elixir.bootlin.com/linux/latest/source/arch/arm/boot/dts/exynos4412.dtsi#L457 > > > Regards, > Lukasz > >> >> Rob >> >> Can I send the next version of the patch set, which has Chanwoo's suggestions, or do you have some objections to this PPMU entries? Regards, Lukasz
