On 3/20/19 4:48 PM, Atish Patra wrote:
The cpu-map DT entry in ARM can describe the CPU topology in much better
way compared to other existing approaches. RISC-V can easily adopt this
binding to represent its 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 significant 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.
There was an opportunity to unify topology data structure for ARM32 done
by patch 3/4. But, I refrained from making any other changes as I am not
very well versed with original intention for some functions that
are present in arch_topology.c. I hope this patch series can be served
as a baseline for such changes in the future.
The patches have been tested for RISC-V and compile tested for ARM64,
ARM32 & x86.
The socket change[2] is also now part of this series.
[1] https://lkml.org/lkml/2018/11/6/19
[2] https://lkml.org/lkml/2018/11/7/918
QEMU changes for RISC-V topology are available at
https://github.com/atishp04/qemu/tree/riscv_topology_dt
HiFive Unleashed DT with topology node is available here.
https://github.com/atishp04/opensbi/tree/HiFive_unleashed_topology
It can be verified with OpenSBI with following additional compile time
option.
FW_PAYLOAD_FDT="unleashed_topology.dtb"
Changes from v2->v3
1. Cover letter update with experiment DT for topology changes.
2. Added the patch for [2].
Changes from v1->v2
1. ARM32 can now use the common code as well.
Atish Patra (4):
dt-binding: cpu-topology: Move cpu-map to a common binding.
cpu-topology: Move cpu topology code to common code.
arm: Use common cpu_topology
RISC-V: Parse cpu topology during boot.
Sudeep Holla (1):
Documentation: DT: arm: add support for sockets defining package
boundaries
.../topology.txt => cpu/cpu-topology.txt} | 134 ++++++--
arch/arm/include/asm/topology.h | 22 +-
arch/arm/kernel/topology.c | 10 +-
arch/arm64/include/asm/topology.h | 23 --
arch/arm64/kernel/topology.c | 303 +-----------------
arch/riscv/Kconfig | 1 +
arch/riscv/kernel/smpboot.c | 3 +
drivers/base/arch_topology.c | 298 ++++++++++++++++-
drivers/base/topology.c | 1 +
include/linux/arch_topology.h | 36 +++
10 files changed, 453 insertions(+), 378 deletions(-)
rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%)
--
2.21.0
Ping?
Specifically, patch 3 & 4 affects ARM & ARM64. Any tests on real
hardware would be great.
Regards,
Atish
