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From: Atish Patra <atish.patra@wdc.com>
To: linux-kernel@vger.kernel.org
Cc: Atish Patra <atish.patra@wdc.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Andreas Schwab <schwab@suse.de>, Anup Patel <anup@brainfault.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	devicetree@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	Jeremy Linton <jeremy.linton@arm.com>,
	linux-riscv@lists.infradead.org,
	Mark Rutland <mark.rutland@arm.com>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Otto Sabart <ottosabart@seberm.com>,
	Palmer Dabbelt <palmer@sifive.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will.deacon@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [RFT PATCH v5 0/5] Unify CPU topology across ARM & RISC-V
Date: Thu, 23 May 2019 17:06:47 -0700	[thread overview]
Message-ID: <20190524000653.13005-1-atish.patra@wdc.com> (raw)

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 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 (1):
Documentation: DT: arm: add support for sockets defining package
boundaries

.../topology.txt => cpu/cpu-topology.txt}     | 134 ++++++--
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/arch_topology.c                  | 298 +++++++++++++++++
include/linux/arch_topology.h                 |  26 ++
include/linux/topology.h                      |   1 +
10 files changed, 444 insertions(+), 425 deletions(-)
rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%)

--
2.21.0


             reply	other threads:[~2019-05-24  0:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-24  0:06 Atish Patra [this message]
2019-05-24  0:06 ` [RFT PATCH v5 1/5] Documentation: DT: arm: add support for sockets defining package boundaries Atish Patra
2019-05-24  0:06 ` [RFT PATCH v5 2/5] dt-binding: cpu-topology: Move cpu-map to a common binding Atish Patra
2019-05-24  0:06 ` [RFT PATCH v5 3/5] cpu-topology: Move cpu topology code to common code Atish Patra
2019-05-24  8:13   ` Greg Kroah-Hartman
2019-05-24  8:57     ` Sudeep Holla
2019-05-24  9:38       ` Will Deacon
2019-05-29 10:48   ` Sudeep Holla
2019-05-29 17:24     ` Atish Patra
2019-05-24  0:06 ` [RFT PATCH v5 4/5] arm: Use common cpu_topology structure and functions Atish Patra
2019-05-29 15:10   ` Sudeep Holla
2019-05-24  0:06 ` [RFT PATCH v5 5/5] RISC-V: Parse cpu topology during boot Atish Patra

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