cc mtk-vpu expert irui.wang.
On Sat, 2021-12-04 at 22:47 +0800, Dafna Hirschfeld wrote:
> From: Alexandre Courbot <acourbot@xxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxx>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> Reviewed-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
> ---
> changes since v4:
> 1. replace data[SHARE_BUF_SIZE]; with data[sizeof(send_obj-
> >share_buf)]
> 2. Add the explanation for the failure in commit log and inline doc
>
> changes since v3:
> 1. multile -> multiple
> 2. add inline doc
>
> 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 | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c
> b/drivers/media/platform/mtk-vpu/mtk_vpu.c
> index 7f1647da0ade..2ef93db239b9 100644
> --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
> @@ -349,7 +349,22 @@ int vpu_ipi_send(struct platform_device *pdev,
> }
> } while (vpu_cfg_readl(vpu, HOST_TO_VPU));
>
> - memcpy_toio(send_obj->share_buf, buf, len);
> + /*
> + * On Arm64, the memcpy_toio does byte-size access as long as
> address or length are
> + * not 8 aligned. Access to the vpu iomem must be 4 aligned.
> Byte-size access is
> + * not allowed and cause processing to fail. Therefore make
> sure the length
> + * sent to memcpy_toio is a multiply of 8.
> + */
> + if (len % 8 != 0) {
> + unsigned char data[sizeof(send_obj->share_buf)];
> +
> + 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);
>
> --
> 2.17.1
>
