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From: Dave.Martin@arm.com (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [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: 20+ 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
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
2013-10-01 19:55   ` Nicolas Pitre
2013-10-02 13:05     ` Dave Martin [this message]
2013-10-02 12:55   ` Dave Martin
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
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
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
     [not found] <20131007140343.GA12030@localhost.localdomain>
2013-10-07 22:06 ` [PATCH 3/6] ARM: EXYNOS: add Exynos Dual Cluster Support Nicolas Pitre

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