On Sat, Jan 12, 2013 at 03:54:42PM +0000, Rob Herring wrote: > On 01/10/2013 07:47 AM, Michal Simek wrote: > > Hi Rob, Mark, Grant and others, > > > > I want to check with you the location of ARM pmu node > > I see that > > 1) highbank and dbx5x0 have it in soc node > > > > 2) vexpress and tegra have no main bus and pmu is in root like all > > others devices. > > (Any reason no to have main bus? Does it mean that there is no bus or > > that all > > devices are accessible?) > > That seems really wrong in general. Any memory mapped device is on a bus > of some kind. I'm not sure the reasoning. Perhaps Stephen can explain. > > > 3) omap2/omap3 have added pmu node to root node(mailing list) > > > > 4) Just for completeness no platform has it in the bus. > > > > > > That's why I have obvious question what it is proper location for pmu node? > > Obviously, highbank is the true and correct way. ;) > > The pmu is part of the cpu, so it could be part of /cpus. That may cause > problems having non-cpu nodes and it would not get probed (although > technically that is a Linux problem and should not influence the DT).
If we were going to allow cpu nodes in /cpus, I'd rather we supported a pmu node in each /cpus/cpuN node. That way the description of heterogeneous clusters would be intuitive (each pmu node representing a single cpu-affine unit rather than the collection of all cpu-affine units). That way describing heterogeneous clusters would become intuitive (cpu affinity would be implicit, and wouldn't have to be described separately as with my proposed binding [1]). and I'm not sure how you'd handle PMUs which used the same PPI > Since it is not on a bus, then putting it at the top level probably > makes more sense than on a bus. Agreed. I think this makes the most sense. > > Rob > > > > > Thanks, > > Michal > > > Thanks, Mark. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2012-December/137290.html _______________________________________________ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss