Re: [PATCH v3] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer

From: houlong wei <houlong.wei@mediatek.com>
To: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Cc: "linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
	"linux-mediatek@lists.infradead.org"
	<linux-mediatek@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Alexandre Courbot" <acourbot@chromium.org>,
	"kernel@collabora.com" <kernel@collabora.com>,
	"Enric Balletbo i Serra" <enric.balletbo@collabora.com>,
	"hverkuil@xs4all.nl" <hverkuil@xs4all.nl>,
	"dafna3@gmail.com" <dafna3@gmail.com>,
	"mchehab@kernel.org" <mchehab@kernel.org>,
	"tfiga@chromium.org" <tfiga@chromium.org>,
	"Minghsiu Tsai (蔡明修)" <Minghsiu.Tsai@mediatek.com>,
	"Andrew-CT Chen (陳智迪)" <Andrew-CT.Chen@mediatek.com>,
	"Tiffany Lin (林慧珊)" <tiffany.lin@mediatek.com>,
	"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	"courbot@chromium.org" <courbot@chromium.org>,
	"hsinyi@chromium.org" <hsinyi@chromium.org>,
	"eizan@chromium.org" <eizan@chromium.org>,
	houlong.wei@mediatek.com
Subject: Re: [PATCH v3] media: mtk-vpu: Ensure alignment of 8 for DTCM buffer
Date: Wed, 25 Aug 2021 18:28:16 +0800	[thread overview]
Message-ID: <1629887296.13994.1.camel@mhfsdcap03> (raw)
In-Reply-To: <20210825101717.18075-1-dafna.hirschfeld@collabora.com>

On Wed, 2021-08-25 at 18:17 +0800, Dafna Hirschfeld wrote:
> 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 patch ensures the copy of a multile 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: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> ---

Reviewed-by: Houlong Wei <houlong.wei@mediatek.com>

> changes since v2:
> 1. do the extra copy only if len is not multiple of 8
> 
> changes since v1:
> 1. change sign-off-by tags
> 2. change values to memset
> 
>  drivers/media/platform/mtk-vpu/mtk_vpu.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c
> index ec290dde59cf..658161ee3e4e 100644
> --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
> @@ -349,7 +349,16 @@ int vpu_ipi_send(struct platform_device *pdev,
>  		}
>  	} while (vpu_cfg_readl(vpu, HOST_TO_VPU));
>  
> -	memcpy_toio(send_obj->share_buf, buf, len);
> +	if (len % 8 != 0) {
> +		unsigned char data[SHARE_BUF_SIZE];
> +
> +		memset(data + len, 0, sizeof(data) - len);
> +		memcpy(data, buf, len);
> +		memcpy_toio(send_obj->share_buf, data, round_up(len, 8));
> +	} else {
> +		memcpy_toio(send_obj->share_buf, buf, len);
> +	}
> +
>  	writel(len, &send_obj->len);
>  	writel(id, &send_obj->id);
>  

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