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    Subject[PATCH v7 0/7] Unify CPU topology across ARM & RISC-V
    Date
    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.

    From Jeremy,

    "I applied these to 5.2rc2, along with my PPTT/MT change and verified the
    system & scheduler topology/etc on DAWN and ThunderX2 using ACPI on arm64.
    They appear to be working correctly.

    so for the series,
    Tested-by: Jeremy Linton <jeremy.linton@arm.com>"

    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 v6->v7
    1. Added socket to HiFive Unleashed topology example.
    2. Added Acked-by & Reviewed-by.

    Changes from v5->v6
    1. Added two more patches from Sudeep about maintainership of arch_topology.c
    and Kconfig update.
    2. Added Tested-by & Reviewed-by
    3. Fixed a nit (reordering of variables)

    Changes from v4-v5
    1. Removed the arch_topology.h header inclusion from topology.c and arch_topology.c
    file. Added it in linux/topology.h.
    2. core_id is set to -1 upon reset. Otherwise, ARM topology store function does not
    work.

    Changes from v3->v4
    1. Get rid of ARM32 specific information in topology structure.
    2. Remove redundant functions from ARM32 and use common code instead.

    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 structure and functions.
    RISC-V: Parse cpu topology during boot.

    Sudeep Holla (3):
    Documentation: DT: arm: add support for sockets defining package
    boundaries
    base: arch_topology: update Kconfig help description
    MAINTAINERS: Add an entry for generic architecture topology

    .../topology.txt => cpu/cpu-topology.txt} | 136 ++++++--
    MAINTAINERS | 7 +
    arch/arm/include/asm/topology.h | 20 --
    arch/arm/kernel/topology.c | 60 +---
    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/Kconfig | 2 +-
    drivers/base/arch_topology.c | 298 +++++++++++++++++
    include/linux/arch_topology.h | 26 ++
    include/linux/topology.h | 1 +
    12 files changed, 454 insertions(+), 426 deletions(-)
    rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%)

    --
    2.21.0

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