linux-kernel - Re: [PATCH 11/21] iommu/mediatek: Add power-domain operation

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Date:   Fri, 7 Aug 2020 10:13:58 +0800
From:   Yong Wu <yong.wu@...iatek.com>
To:     chao hao <Chao.Hao@...iatek.com>
CC:     Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Will Deacon <will@...nel.org>,
        Evan Green <evgreen@...omium.org>,
        Tomasz Figa <tfiga@...gle.com>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <iommu@...ts.linux-foundation.org>, <youlin.pei@...iatek.com>,
        Nicolas Boichat <drinkcat@...omium.org>,
        <anan.sun@...iatek.com>, <cui.zhang@...iatek.com>,
        <ming-fan.chen@...iatek.com>, chao hao <"Chao. Hao"@mediatek.com>
Subject: Re: [PATCH 11/21] iommu/mediatek: Add power-domain operation

On Mon, 2020-07-27 at 16:49 +0800, chao hao wrote:
> On Sat, 2020-07-11 at 14:48 +0800, Yong Wu wrote:
> > In the previous SoC, the M4U HW is in the EMI power domain which is
> > always on. the latest M4U is in the display power domain which may be
> > turned on/off, thus we have to add pm_runtime interface for it.
> > 
> > we should enable its power before M4U hw initial. and disable it after HW
> > initialize.
> > 
> > When the engine work, the engine always enable the power and clocks for
> > smi-larb/smi-common, then the M4U's power will always be powered on
> > automatically via the device link with smi-common.
> > 
> > Note: we don't enable the M4U power in iommu_map/unmap for tlb flush.
> > If its power already is on, of course it is ok. if the power is off,
> > the main tlb will be reset while M4U power on, thus the tlb flush while
> > m4u power off is unnecessary, just skip it.
> > 
> > Signed-off-by: Yong Wu <yong.wu@...iatek.com>

...

> >  
> >  	if (data->plat_data->m4u_plat == M4U_MT8173) {
> > @@ -728,7 +756,15 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >  
> >  	platform_set_drvdata(pdev, data);
> >  
> > +	if (dev->pm_domain)
> > +		pm_runtime_enable(dev);
> 
> hi yong,
> 
> If you put "pm_runtime_enable" here, it maybe not device_link with
> smi_common for previous patch: 
> if(i || !pm_runtime_enabled(dev))
>     continue;
> 
> Whether put it up front?

Thanks for review. My fault here. I will fix it.

> 
> best regards,
> chao