From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
linux-pm@vger.kernel.org, lorenzo.pieralisi@arm.com,
Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>,
Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Nicolas Pitre <nico@fluxnic.net>,
Lior Amsalem <alior@marvell.com>,
Maen Suleiman <maen@marvell.com>,
Tawfik Bayouk <tawfik@marvell.com>,
Shadi Ammouri <shadi@marvell.com>,
Eran Ben-Avi <benavi@marvell.com>,
Yehuda Yitschak <yehuday@marvell.com>,
Nadav Haklai <nadavh@marvell.com>,
Ike Pan <ike.pan@canonical.com>,
Dan Frazier <dann.frazier@canonical.com>,
Leif Lindholm <leif.lindholm@arm.com>,
Jon Masters <jcm@redhat.com>, David Marlin <dmarlin@redhat.com>
Subject: Re: [PATCH v3 05/14] ARM: mvebu: Make ll_set_cpu_coherent() more configurable
Date: Mon, 14 Oct 2013 16:26:36 +0200 [thread overview]
Message-ID: <20131014162636.1f486053@skate> (raw)
In-Reply-To: <1381759106-15004-6-git-send-email-gregory.clement@free-electrons.com>
Dear Gregory CLEMENT,
On Mon, 14 Oct 2013 15:58:17 +0200, Gregory CLEMENT wrote:
> ll_set_cpu_coherent does two things to set the coherency for a CPU:
>
> - Adding the CPU to the SMP group 0
> - Enabling the snooping on the CPU
>
> Only the second part is needed when coming back from a CPU Idle. This
> commit allows to choose to do the first part or not.
I am not a fan of this change: those two boolean arguments are really
mystical. If a function does do things, and sometimes must be called to
do one thing, and sometimes for two things, it is really calling for a
split of the functions (with potentially the second function calling the
first, or the two functions being called in a row when needed).
Let's have two functions:
ll_set_cpu_smp_group();
ll_set_cpu_coherent();
at initialization time, both functions are called. On the exit path of
idle, only the second one is called.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 05/14] ARM: mvebu: Make ll_set_cpu_coherent() more configurable
Date: Mon, 14 Oct 2013 16:26:36 +0200 [thread overview]
Message-ID: <20131014162636.1f486053@skate> (raw)
In-Reply-To: <1381759106-15004-6-git-send-email-gregory.clement@free-electrons.com>
Dear Gregory CLEMENT,
On Mon, 14 Oct 2013 15:58:17 +0200, Gregory CLEMENT wrote:
> ll_set_cpu_coherent does two things to set the coherency for a CPU:
>
> - Adding the CPU to the SMP group 0
> - Enabling the snooping on the CPU
>
> Only the second part is needed when coming back from a CPU Idle. This
> commit allows to choose to do the first part or not.
I am not a fan of this change: those two boolean arguments are really
mystical. If a function does do things, and sometimes must be called to
do one thing, and sometimes for two things, it is really calling for a
split of the functions (with potentially the second function calling the
first, or the two functions being called in a row when needed).
Let's have two functions:
ll_set_cpu_smp_group();
ll_set_cpu_coherent();
at initialization time, both functions are called. On the exit path of
idle, only the second one is called.
Best regards,
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2013-10-14 14:26 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-14 13:58 [PATCH v3 00/14] CPU idle for Armada XP Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 13:58 ` [PATCH v3 01/14] ARM: PJ4B: Add cpu_suspend/cpu_resume hooks for PJ4B Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 13:58 ` [PATCH v3 02/14] ARM: mvebu: ll_set_cpu_coherent no more uses the coherency address as parameter Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:20 ` Thomas Petazzoni
2013-10-14 14:20 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 03/14] ARM: mvebu: ll_set_cpu_coherent always uses the current CPU Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:22 ` Thomas Petazzoni
2013-10-14 14:22 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 04/14] ARM: mvebu: Remove the unused argument of set_cpu_coherent() Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:23 ` Thomas Petazzoni
2013-10-14 14:23 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 05/14] ARM: mvebu: Make ll_set_cpu_coherent() more configurable Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:26 ` Thomas Petazzoni [this message]
2013-10-14 14:26 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 06/14] ARM: mvebu: Low level functions to disable cache snooping Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:32 ` Thomas Petazzoni
2013-10-14 14:32 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 07/14] ARM: mvebu: Add a new set of registers for pmsu Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:34 ` Thomas Petazzoni
2013-10-14 14:34 ` Thomas Petazzoni
2013-10-14 14:36 ` Jason Cooper
2013-10-14 14:36 ` Jason Cooper
2013-10-14 13:58 ` [PATCH v3 08/14] ARM: mvebu: Allow to power down L2 cache controller in idle mode Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:44 ` Thomas Petazzoni
2013-10-14 14:44 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 09/14] ARM: mvebu: Add the PMSU related part of the cpu idle functions Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 14:54 ` Thomas Petazzoni
2013-10-14 14:54 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 10/14] ARM: mvebu: Set the start address of a CPU in a separate function Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 13:58 ` [PATCH v3 11/14] ARM: mvebu: Add CPU idle low level support for Marvell Armada XP Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 16:28 ` Thomas Petazzoni
2013-10-14 16:28 ` Thomas Petazzoni
2013-10-14 13:58 ` [PATCH v3 12/14] cpuidle: mvebu: Add initial CPU idle support for Armada 370/XP SoC Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 16:36 ` Thomas Petazzoni
2013-10-14 16:36 ` Thomas Petazzoni
2013-10-17 10:15 ` Daniel Lezcano
2013-10-17 10:15 ` Daniel Lezcano
2013-10-14 13:58 ` [PATCH v3 13/14] ARM: mvebu: register the cpuidle driver for the Armada XP SoCs Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
2013-10-14 13:58 ` [PATCH v3 14/14] ARM: dts: mvebu: Add a new set of registers to the PMSU node Gregory CLEMENT
2013-10-14 13:58 ` Gregory CLEMENT
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