On 20/09/2021 19:04, 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
Why do errors appear? Is that due to a HW bug? Some other reason?
>
> 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: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
> Reviewed-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
> ---
> 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 | 15 ++++++++++++++-
> 1 file changed, 14 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..1df031716c8f 100644
> --- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
> +++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
> @@ -349,7 +349,20 @@ int vpu_ipi_send(struct platform_device *pdev,
> }
> } while (vpu_cfg_readl(vpu, HOST_TO_VPU));
>
> - memcpy_toio(send_obj->share_buf, buf, len);
> + /*
> + * when copying data to the vpu hardware, the memcpy_toio operation must copy
> + * a multiple of 8. Otherwise the processing fails
Same here: it needs to explain why the processing fails.
> + */
> + if (len % 8 != 0) {
> + unsigned char data[SHARE_BUF_SIZE];
Wouldn't it be more robust if you say:
unsigned char data[sizeof(send_obj->share_buf)];
I also think that the SHARE_BUF_SIZE define needs a comment stating that it must be a
multiple of 8, otherwise unexpected things can happen.
You also noticed that the current SHARE_BUF_SIZE define is too low, but I saw
no patch correcting this. Shouldn't that be fixed as well?
Regards,
Hans
> +
> + 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);
>
>
