devicetree.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Dave Martin <Dave.Martin@arm.com>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, Kukjin Kim <kgene.kim@samsung.com>,
	Russell King <linux@arm.linux.org.uk>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Stephen Warren <swarren@wwwdotorg.org>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Rob Herring <rob.herring@calxeda.com>,
	linux-samsung-soc@vger.kernel.org,
	Vyacheslav Tyrtov <v.tyrtov@samsung.com>,
	Ben Dooks <ben-linux@fluff.org>,
	Tarek Dakhran <t.dakhran@samsung.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Rob Landley <rob@landley.net>, Heiko Stuebner <heiko@sntech.de>,
	Mike Turquette <mturquette@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	Naour Romain <romain.naour@openwide.fr>
Subject: Re: [PATCH 3/6] ARM: EXYNOS: add Exynos Dual Cluster Support
Date: Wed, 2 Oct 2013 14:05:50 +0100	[thread overview]
Message-ID: <20131002130550.GB3407@localhost.localdomain> (raw)
In-Reply-To: <alpine.LFD.2.03.1310011451390.21228@syhkavp.arg>

On Tue, Oct 01, 2013 at 03:55:24PM -0400, Nicolas Pitre wrote:
> On Tue, 1 Oct 2013, Vyacheslav Tyrtov wrote:
> 
> > From: Tarek Dakhran <t.dakhran@samsung.com>

[...]

> > +	kfs_use_count[cpu][cluster]++;
> > +	if (kfs_use_count[cpu][cluster] == 1) {
> > +		++core_count[cluster];
> > +		if (core_count[cluster] == 1) {
> > +			ret = exynos_cluster_power_up(cluster);
> > +			if (ret) {
> > +				pr_err("%s: cluster %u power up error\n",
> > +					__func__, cluster);
> > +				return ret;
> > +			}
> > +			__cci_control_port_by_index(MAX_NR_CLUSTERS
> > +					 - cluster, true);
> 
> This is wrong and very racy.  The state machine implemented in 
> mcpm-head.S is there already to handle proper synchronization for you.  

Maybe this issue didn't make itself obvious yet due to the lack of
suspend support.

Moving the CCI maintenance to power_up_setup() is essential for suspend/
resume to work, because then CPUs can power up randomly in response to
interrupts -- exynos_lock is not sufficient protection in that case.

The TC2 code should provide a good example of what to do.

[...]

Cheers
---Dave

  reply	other threads:[~2013-10-02 13:05 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-01 16:17 [PATCH 0/6] Exynos 5410 Dual cluster support Vyacheslav Tyrtov
2013-10-01 16:17 ` [PATCH 1/6] ARM: EXYNOS: Add support for EXYNOS5410 SoC Vyacheslav Tyrtov
2013-10-01 16:17 ` [PATCH 2/6] clk: exynos5410: register clocks using common clock framework Vyacheslav Tyrtov
2013-10-01 17:07   ` Bartlomiej Zolnierkiewicz
     [not found]   ` <1380644227-12244-3-git-send-email-v.tyrtov-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-10-01 21:44     ` Stephen Warren
2013-10-02 20:32   ` Tomasz Figa
2013-10-01 16:17 ` [PATCH 3/6] ARM: EXYNOS: add Exynos Dual Cluster Support Vyacheslav Tyrtov
     [not found]   ` <1380644227-12244-4-git-send-email-v.tyrtov-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-10-01 19:55     ` Nicolas Pitre
2013-10-02 13:05       ` Dave Martin [this message]
2013-10-02 12:55   ` Dave Martin
     [not found]     ` <20131002125458.GA3407-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2013-10-04 19:51       ` Nicolas Pitre
2013-10-01 16:17 ` [PATCH 4/6] ARM: dts: Add initial device tree support for EXYNOS5410 Vyacheslav Tyrtov
     [not found]   ` <1380644227-12244-5-git-send-email-v.tyrtov-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-10-02 20:54     ` Tomasz Figa
2013-10-01 16:17 ` [PATCH 5/6] ARM: EXYNOS: Minor fixes to enable EXYNOS5410 support Vyacheslav Tyrtov
     [not found]   ` <1380644227-12244-6-git-send-email-v.tyrtov-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-10-01 17:37     ` Bartlomiej Zolnierkiewicz
2013-10-02 21:07   ` Tomasz Figa
2013-10-03  6:16     ` Chander Kashyap
2013-10-01 16:17 ` [PATCH 6/6] ARM: smdk5410_defconfig: add defconfig for smdk5410 Vyacheslav Tyrtov
2013-10-01 17:48   ` Bartlomiej Zolnierkiewicz
  -- strict thread matches above, loose matches on Subject: below --
2013-10-07 14:03 [PATCH 3/6] ARM: EXYNOS: add Exynos Dual Cluster Support Dave Martin
2013-10-07 22:06 ` Nicolas Pitre

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=20131002130550.GB3407@localhost.localdomain \
    --to=dave.martin@arm.com \
    --cc=ben-linux@fluff.org \
    --cc=daniel.lezcano@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=heiko@sntech.de \
    --cc=ijc+devicetree@hellion.org.uk \
    --cc=kgene.kim@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=linux@arm.linux.org.uk \
    --cc=mark.rutland@arm.com \
    --cc=mturquette@linaro.org \
    --cc=nicolas.pitre@linaro.org \
    --cc=pawel.moll@arm.com \
    --cc=rob.herring@calxeda.com \
    --cc=rob@landley.net \
    --cc=romain.naour@openwide.fr \
    --cc=swarren@wwwdotorg.org \
    --cc=t.dakhran@samsung.com \
    --cc=tglx@linutronix.de \
    --cc=v.tyrtov@samsung.com \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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).