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Subject: Re: [PATCH v7, 12/15] media: mtk-vcodec: Support 34bits dma address
 for vdec
To:     Yunfei Dong <yunfei.dong@mediatek.com>,
        Alexandre Courbot <acourbot@chromium.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Tzung-Bi Shih <tzungbi@chromium.org>,
        Tiffany Lin <tiffany.lin@mediatek.com>,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Tomasz Figa <tfiga@google.com>
Cc:     Hsin-Yi Wang <hsinyi@chromium.org>,
        Fritz Koenig <frkoenig@chromium.org>,
        Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Irui Wang <irui.wang@mediatek.com>,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        srv_heupstream@mediatek.com, linux-mediatek@lists.infradead.org,
        Project_Global_Chrome_Upstream_Group@mediatek.com
References: <20211011070247.792-1-yunfei.dong@mediatek.com>
 <20211011070247.792-13-yunfei.dong@mediatek.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Message-ID: <5e1c165d-176c-0141-dc96-0fdbda367c03@collabora.com>
Date:   Thu, 14 Oct 2021 13:02:51 +0200
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> Use the dma_set_mask_and_coherent helper to set vdec
> DMA bit mask to support 34bits iova space(16GB) that
> the mt8192 iommu HW support.
> 
> Whole the iova range separate to 0~4G/4G~8G/8G~12G/12G~16G,
> regarding which iova range VDEC actually locate, it
> depends on the dma-ranges property of vdec dtsi node.
> 
> Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> ---
>   drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> index de83e3b821b4..da963cdac96b 100644
> --- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> +++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> @@ -376,6 +376,9 @@ static int mtk_vcodec_probe(struct platform_device *pdev)
>   		}
>   	}
>   
> +	if (of_get_property(pdev->dev.of_node, "dma-ranges", NULL))
> +		dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(34));
> +

This function returns 0 for success, or negative number for failure: please check
the return value, or this driver may not work correctly in some corner cases.

Regards,
- Angelo

>   	for (i = 0; i < MTK_VDEC_HW_MAX; i++)
>   		mutex_init(&dev->dec_mutex[i]);
>   	spin_lock_init(&dev->irqlock);
>