linux-kernel - Re: [PATCH v2 16/29] iommu/mediatek: Adjust device link when it is sub-common

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Message-ID: <CAJMQK-ir-wLy4OHkWEWZf=CZcURMhRvHnOjBLWXaezhukJh2JA@mail.gmail.com>
Date:   Tue, 24 Aug 2021 15:35:05 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     Yong Wu <yong.wu@...iatek.com>
Cc:     Joerg Roedel <joro@...tes.org>, Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Evan Green <evgreen@...omium.org>,
        Tomasz Figa <tfiga@...gle.com>,
        Tomasz Figa <tfiga@...omium.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>, srv_heupstream@...iatek.com,
        Devicetree List <devicetree@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        iommu@...ts.linux-foundation.org, youlin.pei@...iatek.com,
        Nicolas Boichat <drinkcat@...omium.org>, anan.sun@...iatek.com,
        chao.hao@...iatek.com
Subject: Re: [PATCH v2 16/29] iommu/mediatek: Adjust device link when it is sub-common

On Fri, Aug 13, 2021 at 3:03 PM Yong Wu <yong.wu@...iatek.com> wrote:
>
> For MM IOMMU, We always add device link between smi-common and IOMMU HW.
> In mt8195, we add smi-sub-common. Thus, if the node is sub-common, we still
> need find again to get smi-common, then do device link.
>
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> ---
>  drivers/iommu/mtk_iommu.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index a4479916ad33..a72241724adb 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -845,6 +845,17 @@ static int mtk_iommu_mm_dts_parse(struct device *dev,
>         if (!smicomm_node)
>                 return -EINVAL;
>
> +       /* Find smi-common again if this is smi-sub-common */
> +       if (of_property_read_bool(smicomm_node, "mediatek,smi_sub_common")) {
> +               of_node_put(smicomm_node); /* put the sub common */
> +
> +               smicomm_node = of_parse_phandle(smicomm_node, "mediatek,smi", 0);

This only checks 1 level here, and does not check if the mediatek,smi
of a sub-common node is not another sub-common node.
So maybe add a check that the updated node here doesn't have
mediatek,smi_sub_common property.

> +               if (!smicomm_node) {
> +                       dev_err(dev, "sub-comm has no common.\n");
> +                       return -EINVAL;
> +               }
> +       }
> +
>         plarbdev = of_find_device_by_node(smicomm_node);
>         of_node_put(smicomm_node);
>         data->smicomm_dev = &plarbdev->dev;
> --
> 2.18.0
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek

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