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Date:   Fri, 28 Jan 2022 13:45:40 +0100
From:   Mauro Carvalho Chehab <mchehab@kernel.org>
To:     Yong Wu <yong.wu@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>
Cc:     Hans Verkuil <hverkuil@xs4all.nl>, Joerg Roedel <jroedel@suse.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        David Airlie <airlied@linux.ie>,
        Evan Green <evgreen@chromium.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Tomasz Figa <tfiga@chromium.org>,
        Will Deacon <will.deacon@arm.com>,
        <linux-mediatek@lists.infradead.org>,
        <srv_heupstream@mediatek.com>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <iommu@lists.linux-foundation.org>, <youlin.pei@mediatek.com>,
        Matthias Kaehlcke <mka@chromium.org>, <anan.sun@mediatek.com>,
        <yi.kuo@mediatek.com>, <acourbot@chromium.org>,
        <linux-media@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Tiffany Lin <tiffany.lin@mediatek.com>,
        "Dafna Hirschfeld" <dafna.hirschfeld@collabora.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Eizan Miyamoto <eizan@chromium.org>,
        <anthony.huang@mediatek.com>,
        Frank Wunderlich <frank-w@public-files.de>,
        <mingyuan.ma@mediatek.com>, <yf.wang@mediatek.com>,
        <libo.kang@mediatek.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Subject: Re: [PATCH v10 02/13] iommu/mediatek-v1: Free the existed fwspec if
 the master dev already has
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In-Reply-To: <20220128134055.720bb43c@coco.lan>
References: <20220117070510.17642-1-yong.wu@mediatek.com>
        <20220117070510.17642-3-yong.wu@mediatek.com>
        <20220128134055.720bb43c@coco.lan>
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Em Fri, 28 Jan 2022 13:40:55 +0100
Mauro Carvalho Chehab <mchehab@kernel.org> escreveu:

> Hi Matthias/Yong,
> 
> Are you ok if this patch gets merged via the media tree together with the
> remaining series, or do you prefer to apply it via SoC tree instead?

Same questions for other patches touching files outside drivers/media
on this pull request:

	https://patchwork.kernel.org/project/linux-mediatek/patch/7af52d61-47c7-581d-62ed-76a7f8315b16@xs4all.nl/

Like those:
	0004-0013-iommu-mediatek-v1-Free-the-existed-fwspec-if-the-mas.patch
	0005-0013-iommu-mediatek-Return-ENODEV-if-the-device-is-NULL.patch
	0006-0013-iommu-mediatek-Add-probe_defer-for-smi-larb.patch
	0007-0013-iommu-mediatek-Add-device_link-between-the-consumer-.patch

Regards,
Mauro

> 
> Regards,
> Mauro
> 
> 
> Em Mon, 17 Jan 2022 15:04:59 +0800
> Yong Wu <yong.wu@mediatek.com> escreveu:
> 
> > When the iommu master device enters of_iommu_xlate, the ops may be
> > NULL(iommu dev is defered), then it will initialize the fwspec here:
> > 
> > [<c0c9c5bc>] (dev_iommu_fwspec_set) from [<c06bda80>]
> > (iommu_fwspec_init+0xbc/0xd4)
> > [<c06bd9c4>] (iommu_fwspec_init) from [<c06c0db4>]
> > (of_iommu_xlate+0x7c/0x12c)
> > [<c06c0d38>] (of_iommu_xlate) from [<c06c10e8>]
> > (of_iommu_configure+0x144/0x1e8)
> > 
> > BUT the mtk_iommu_v1.c only supports arm32, the probing flow still is a bit
> > weird. We always expect create the fwspec internally. otherwise it will
> > enter here and return fail.
> > 
> > static int mtk_iommu_create_mapping(struct device *dev,
> > 				    struct of_phandle_args *args)
> > {
> >         ...
> > 	if (!fwspec) {
> > 	        ....
> > 	} else if (dev_iommu_fwspec_get(dev)->ops != &mtk_iommu_ops) {  
> >                 >>>>>>>>>>Enter here. return fail.<<<<<<<<<<<<    
> > 		return -EINVAL;
> > 	}
> > 	...
> > }
> > 
> > Thus, Free the existed fwspec if the master device already has fwspec.
> > 
> > This issue is reported at:
> > https://lore.kernel.org/linux-mediatek/trinity-7d9ebdc9-4849-4d93-bfb5-429dcb4ee449-1626253158870@3c-app-gmx-bs01/
> > 
> > Reported-by: Frank Wunderlich <frank-w@public-files.de>
> > Tested-by: Frank Wunderlich <frank-w@public-files.de> # BPI-R2/MT7623
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > Acked-by: Joerg Roedel <jroedel@suse.de>
> > Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> > ---
> >  drivers/iommu/mtk_iommu_v1.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> > 
> > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
> > index be22fcf988ce..1467ba1e4417 100644
> > --- a/drivers/iommu/mtk_iommu_v1.c
> > +++ b/drivers/iommu/mtk_iommu_v1.c
> > @@ -425,6 +425,15 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
> >  	struct mtk_iommu_data *data;
> >  	int err, idx = 0;
> >  
> > +	/*
> > +	 * In the deferred case, free the existed fwspec.
> > +	 * Always initialize the fwspec internally.
> > +	 */
> > +	if (fwspec) {
> > +		iommu_fwspec_free(dev);
> > +		fwspec = dev_iommu_fwspec_get(dev);
> > +	}
> > +
> >  	while (!of_parse_phandle_with_args(dev->of_node, "iommus",
> >  					   "#iommu-cells",
> >  					   idx, &iommu_spec)) {  
> 
> 
> 
> Thanks,
> Mauro


Thanks,
Mauro