On 11 Jun 22, Catalin Marinas wrote: > On Tue, Jun 21, 2011 at 01:36:15PM -0700, Stephen Boyd wrote: > > On 06/16/2011 11:54 PM, Vincent Guittot wrote: > > > On 16 June 2011 21:40, Stephen Boyd <sb...@codeaurora.org> wrote: > > >> The ARM ARM says these fields are IMPLEMENTATION DEFINED meaning that > > >> different vendors may attribute different meaning to these fields if > > >> they wish. Does that mean this should be a platform_*() function? > > >> > > > The ARM ARM also provides a recommended use of the fields of this > > > register and the TRM of each Cortex adds some details. On the cortex > > > A9, each platform can only set the value of the Cluster ID with the > > > CLUSTERID pins. I have tried to consolidate the value of MPIDR across > > > several platforms and they all match with the description. > > > > > > Have you got an example of a MPIDR register which doesn't match with > > > the implementation ? > > > > Not that I know of. I'm more concerned with how the ARM ARM has two > > recommended usages for these fields depending on virtualization or not. > > I suppose we can handle that issue when it arises (or does your > > implementation already handle that?) > > According to the ARM ARM: > > MPIDR provides a mechanism with up to three levels of affinity > information, but the meaning of those levels of affinity is > entirely IMPLEMENTATION DEFINED. > > So we can't really tell the meaning of the affinity bits. There are two > recommended ways indeed (with or without virtualisation) which are not > that different with regards to the topology (just introducing another > level for virtual CPUs). > > But I think a more general solution would be for the CPU topology to be > provided via the FDT.
Agreed. That will be the next step. We decided on doing it this way to allow non-DT-enabled platforms to be able to use the feature and to allow DT-enabled platforms to settle down in the mean time. _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev