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

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Date:	Mon, 02 Jun 2014 18:05:04 +0200
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
CC:	Kukjin Kim <kgene.kim@...sung.com>,
	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 06/02/2014 02:08 PM, Bartlomiej Zolnierkiewicz wrote:
>
> Hi,
>
> On Friday, May 16, 2014 11:03:11 AM Daniel Lezcano wrote:
>> 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() ?
>
> I would prefer to keep this code close to exynos_pm_central_suspend()
> because exynos_pm_suspend() (which calls exynos_pm_central_suspend()
> too) also contains S5P_USE_STANDBY_WF[I,E]0 setting code (done for all
> SoCs).  If possible I would like to make this code common for AFTR &
> suspend in the future (once it is tested on Exynos4210 and Exynos5250)
> by moving S5P_USE_STANDBY_WF[I,E]0 setting to exynos_pm_central_suspend()
> and doing it for all SoCs.  Are you okay with this?

Yeah, no problem.


>>>    			exynos_cpu_save_register();
>>>    		}
>>>    		break;
>
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>


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