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* [PATCH v7 0/7] Unify CPU topology across ARM & RISC-V 
@ 2019-06-17 18:59 Atish Patra
  2019-06-17 18:59 ` [PATCH v7 1/7] Documentation: DT: arm: add support for sockets defining package boundaries Atish Patra
                   ` (6 more replies)
  0 siblings, 7 replies; 19+ messages in thread
From: Atish Patra @ 2019-06-17 18:59 UTC (permalink / raw)
  To: linux-kernel
  Cc: Mark Rutland, Rafael J. Wysocki, Peter Zijlstra \(Intel\),
	Catalin Marinas, Linus Walleij, Palmer Dabbelt, Will Deacon,
	Richard Fontana, Mauro Carvalho Chehab, linux-riscv, Ingo Molnar,
	Anup Patel, Russell King, Morten Rasmussen, devicetree,
	Albert Ou, Rob Herring, Paul Walmsley, Jonathan Cameron,
	Thomas Gleixner, linux-arm-kernel, Atish Patra,
	Greg Kroah-Hartman, Jeremy Linton, Otto Sabart, Sudeep Holla,
	David S. Miller

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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-- links below jump to the message on this page --
2019-06-17 18:59 [PATCH v7 0/7] Unify CPU topology across ARM & RISC-V Atish Patra
2019-06-17 18:59 ` [PATCH v7 1/7] Documentation: DT: arm: add support for sockets defining package boundaries Atish Patra
2019-06-27  0:31   ` Paul Walmsley
2019-06-27  2:18     ` Atish Patra
2019-06-27 19:58       ` Atish Patra
2019-06-17 18:59 ` [PATCH v7 2/7] dt-binding: cpu-topology: Move cpu-map to a common binding Atish Patra
2019-06-17 18:59 ` [PATCH v7 3/7] cpu-topology: Move cpu topology code to common code Atish Patra
2019-06-19 17:38   ` Greg Kroah-Hartman
2019-06-21 22:31     ` Atish Patra
2019-06-23 17:51       ` Paul Walmsley
2019-06-17 18:59 ` [PATCH v7 4/7] arm: Use common cpu_topology structure and functions Atish Patra
2019-06-19 12:10   ` Sudeep Holla
2019-06-24 15:06     ` Sudeep Holla
2019-06-24 15:30       ` Russell King - ARM Linux admin
2019-06-24 15:33         ` Sudeep Holla
2019-06-17 18:59 ` [PATCH v7 5/7] RISC-V: Parse cpu topology during boot Atish Patra
2019-06-17 18:59 ` [PATCH v7 6/7] base: arch_topology: update Kconfig help description Atish Patra
2019-06-17 18:59 ` [PATCH v7 7/7] MAINTAINERS: Add an entry for generic architecture topology Atish Patra
2019-06-19 17:37   ` Greg Kroah-Hartman

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