linux-kernel - Re: [PATCH 6/7] ARM: EXYNOS: PM: fix register setup on EXYNOS4x12 for AFTR mode code

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Message-ID: <5375D44F.7000505@linaro.org>
Date:	Fri, 16 May 2014 11:03:11 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Kukjin Kim <kgene.kim@...sung.com>
CC:	Tomasz Figa <t.figa@...sung.com>,
	Sachin Kamat <sachin.kamat@...aro.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-kernel@...ts.linaro.org
Subject: Re: [PATCH 6/7] ARM: EXYNOS: PM: fix register setup on EXYNOS4x12
 for AFTR mode code

On 05/05/2014 12:57 PM, Bartlomiej Zolnierkiewicz wrote:
> Add S5P_CENTRAL_SEQ_OPTION register setup for EXYNOS4x12 to AFTR
> mode code.  Without this setup AFTR mode doesn't show any benefit
> over WFI one.  When this setup is applied AFTR mode reduces power
> consumption by ~12% (as measured on Trats2 board).
>
> This change is a preparation for adding secure firmware support to
> EXYNOS cpuidle driver.
>
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> ---
>   arch/arm/mach-exynos/pm.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm/mach-exynos/pm.c b/arch/arm/mach-exynos/pm.c
> index 18f6bf8..3922968 100644
> --- a/arch/arm/mach-exynos/pm.c
> +++ b/arch/arm/mach-exynos/pm.c
> @@ -391,6 +391,10 @@ static int exynos_cpu_pm_notifier(struct notifier_block *self,
>   	case CPU_PM_ENTER:
>   		if (cpu == 0) {
>   			exynos_pm_central_suspend();
> +			if (soc_is_exynos4212() || soc_is_exynos4412())
> +				__raw_writel(S5P_USE_STANDBY_WFI0 |
> +					     S5P_USE_STANDBY_WFE0,
> +					     S5P_CENTRAL_SEQ_OPTION);

Why not put this code in the exynos_enter_aftr() ?

>   			exynos_cpu_save_register();
>   		}
>   		break;



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