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Date:   Mon, 29 May 2023 10:31:08 +0200
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Subject: Re: [PATCH v6] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer
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To:     Pin-yen Lin <treapking@chromium.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc:     Tiffany Lin <tiffany.lin@mediatek.com>,
        linux-mediatek@lists.infradead.org,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Minghsiu Tsai <minghsiu.tsai@mediatek.com>,
        Houlong Wei <houlong.wei@mediatek.com>,
        Yunfei Dong <yunfei.dong@mediatek.com>,
        linux-media@vger.kernel.org, Hsin-Yi Wang <hsinyi@chromium.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Alexandre Courbot <acourbot@chromium.org>
References: <20230526063149.1801196-1-treapking@chromium.org>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230526063149.1801196-1-treapking@chromium.org>
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Il 26/05/23 08:31, Pin-yen Lin ha scritto:
> From: Alexandre Courbot <acourbot@chromium.org>
> 
> When running memcpy_toio:
> memcpy_toio(send_obj->share_buf, buf, len);
> it was found that errors appear if len is not a multiple of 8:
> 
> [58.350841] mtk-mdp 14001000.rdma: processing failed: -22
> 
> This is because in ARM64, memcpy_toio does byte-size access
> when the length is not a multiple of 8 while access to the
> vpu iomem must be 4 aligned.
> 
> This patch ensures the copy of a multiple of 8 size by calling
> round_up(len, 8) when copying.
> 
> Fixes: e6599adfad30 ("media: mtk-vpu: avoid unaligned access to DTCM buffer.")
> Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>
> Reviewed-by: Houlong Wei <houlong.wei@mediatek.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> 
> ---
> This is a re-send of v5 because it was marked obsolete, but this patch
> is required for MT8173 platforms.
> 

Hello,
I have solved this issue in a different way and the commit was already picked.

Please check:
ab14c99c035d ("media: platform: mtk-mdp: Fix mdp_ipi_comm structure alignment")

Regards,
Angelo