LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
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>,
	Ard Biesheuvel <ard.biesheuvel@linaro.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 v4 0/5] Unify CPU topology across ARM & RISC-V
Date: Sat, 27 Apr 2019 17:25:24 -0700	[thread overview]
Message-ID: <20190428002529.14229-1-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 v3->v4
1. Get rid of ARM32 specific information in topology strucuture.
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                  | 300 ++++++++++++++++-
drivers/base/topology.c                       |   1 +
include/linux/arch_topology.h                 |  26 ++
10 files changed, 445 insertions(+), 426 deletions(-)
rename Documentation/devicetree/bindings/{arm/topology.txt => cpu/cpu-topology.txt} (66%)

--
2.21.0


             reply	other threads:[~2019-04-28  0:26 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-28  0:25 Atish Patra [this message]
2019-04-28  0:25 ` [RFT PATCH v4 1/5] Documentation: DT: arm: add support for sockets defining package boundaries Atish Patra
2019-04-28  0:25 ` [RFT PATCH v4 2/5] dt-binding: cpu-topology: Move cpu-map to a common binding Atish Patra
2019-04-28  0:25 ` [RFT PATCH v4 3/5] cpu-topology: Move cpu topology code to common code Atish Patra
2019-05-23  9:35   ` Sudeep Holla
2019-05-23 23:34     ` Atish Patra
2019-04-28  0:25 ` [RFT PATCH v4 4/5] arm: Use common cpu_topology structure and functions Atish Patra
2019-04-28  0:25 ` [RFT PATCH v4 5/5] RISC-V: Parse cpu topology during boot Atish Patra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190428002529.14229-1-atish.patra@wdc.com \
    --to=atish.patra@wdc.com \
    --cc=anup@brainfault.org \
    --cc=aou@eecs.berkeley.edu \
    --cc=ard.biesheuvel@linaro.org \
    --cc=catalin.marinas@arm.com \
    --cc=devicetree@vger.kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=jeremy.linton@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=mark.rutland@arm.com \
    --cc=mingo@kernel.org \
    --cc=morten.rasmussen@arm.com \
    --cc=ottosabart@seberm.com \
    --cc=palmer@sifive.com \
    --cc=paul.walmsley@sifive.com \
    --cc=peterz@infradead.org \
    --cc=rafael@kernel.org \
    --cc=robh+dt@kernel.org \
    --cc=schwab@suse.de \
    --cc=sudeep.holla@arm.com \
    --cc=tglx@linutronix.de \
    --cc=will.deacon@arm.com \
    --subject='Re: [RFT PATCH v4 0/5] Unify CPU topology across ARM & RISC-V' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).