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. 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 :-/ Morten
