On Fri, Dec 07, 2018 at 01:45:21PM +0000, Morten Rasmussen wrote: > Hi, > > On Thu, Nov 29, 2018 at 03:28:16PM -0800, Atish Patra wrote: > > The cpu-map DT entry in ARM64 can describe the CPU topology in > > much better way compared to other existing approaches. RISC-V can > > easily adopt this binding to represent it's own CPU topology. > > Thus, both cpu-map DT binding and topology parsing code can be > > moved to a common location so that RISC-V or any other > > architecture can leverage that. > > > > The relevant discussion regarding unifying cpu topology can be > > found in [1]. > > > > arch_topology seems to be a perfect place to move the common > > code. I have not introduced any functional changes in the moved > > code. The only downside in this approach is that the capacity > > code will be executed for RISC-V as well. But, it will exit > > immediately after not able to find the appropriate DT node. If > > the overhead is considered too much, we can always compile out > > capacity related functions under a different config for the > > architectures that do not support them. > > > > The patches have been tested for RISC-V and compile tested for > > ARM64 & x86. > > The cpu-map bindings are used for arch/arm too, and so is > arch_topology.c. In fact, it was introduced to allow code-sharing > between arm and arm64. Applying patch three breaks arm. > Ah right. Though I remember the whole point of moving these to arch_topology was to share between ARM and ARM64, I completely forgot to check the impact of this for ARM platforms. > Moving the DT parsing to arch_topology.c we have to unify all three > architectures. Be aware that arm and arm64 have some differences in how > they detect cpu capacities. I think we might have to look at the split > of code between arch/* and arch_topology.c again :-/ > Thanks for pointing this out. I completely agree and apologies for forgetting about arm32. Regards, Sudeep
