Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210813065324.29220-1-yong.wu@mediatek.com> <20210813065324.29220-17-yong.wu@mediatek.com>
In-Reply-To: <20210813065324.29220-17-yong.wu@mediatek.com>
From:   Hsin-Yi Wang <hsinyi@chromium.org>
Date:   Tue, 24 Aug 2021 15:35:05 +0800
Message-ID: <CAJMQK-ir-wLy4OHkWEWZf=CZcURMhRvHnOjBLWXaezhukJh2JA@mail.gmail.com>
Subject: Re: [PATCH v2 16/29] iommu/mediatek: Adjust device link when it is sub-common
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Evan Green <evgreen@chromium.org>,
        Tomasz Figa <tfiga@google.com>,
        Tomasz Figa <tfiga@chromium.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>, srv_heupstream@mediatek.com,
        Devicetree List <devicetree@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        iommu@lists.linux-foundation.org, youlin.pei@mediatek.com,
        Nicolas Boichat <drinkcat@chromium.org>, anan.sun@mediatek.com,
        chao.hao@mediatek.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Aug 13, 2021 at 3:03 PM Yong Wu <yong.wu@mediatek.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@mediatek.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@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek