Hi Benjamin,
On Mon, 2021-02-22 at 13:24 +0100, Benjamin Gaignard wrote:
> The HEVC HANTRO driver needs to know the number of bits to skip at
s/HANTRO/Hantro
> the beginning of the slice header.
As discussed in a different thread, we should describe exactly
what the hardware is expecting, so applications can parse that
and pass a correct value.
> That is a hardware specific requirement so create a dedicated control
> that this purpose.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> ---
> version 3:
> - Fix typo in field name
>
> include/uapi/linux/hantro-v4l2-controls.h | 20 ++++++++++++++++++++
> include/uapi/linux/v4l2-controls.h | 5 +++++
> 2 files changed, 25 insertions(+)
> create mode 100644 include/uapi/linux/hantro-v4l2-controls.h
>
> diff --git a/include/uapi/linux/hantro-v4l2-controls.h b/include/uapi/linux/hantro-v4l2-controls.h
> new file mode 100644
> index 000000000000..a8dfd6b1a2a9
> --- /dev/null
> +++ b/include/uapi/linux/hantro-v4l2-controls.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +
> +#ifndef __UAPI_HANTRO_V4L2_CONYTROLS_H__
> +#define __UAPI_HANTRO_V4L2_CONYTROLS_H__
> +
> +#include <linux/v4l2-controls.h>
> +#include <media/hevc-ctrls.h>
> +
> +#define V4L2_CID_HANTRO_HEVC_EXTRA_DECODE_PARAMS (V4L2_CID_USER_HANTRO_BASE + 0)
> +
> +/**
> + * struct hantro_hevc_extra_decode_params - extra decode parameters for hantro driver
> + * @hevc_hdr_skip_length: header first bits offset
> + */
> +struct hantro_hevc_extra_decode_params {
> + __u32 hevc_hdr_skip_length;
> + __u8 padding[4];
> +};
> +
I think we can get away with a simpler solution. Since it's just one integer
we need, there's no need for a compound control. Something like this:
.codec = HANTRO_HEVC_DECODER,
.cfg = {
.id = V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP,
.name = "Hantro HEVC slice header skip bytes",
.type = V4L2_CTRL_TYPE_INTEGER,
.min = 0,
.max = 0x7fffffff,
.step = 1,
},
Also see V4L2_CID_CODA_MB_ERR_CNT which is defined in drivers/media/platform/coda/coda.h.
The control is sufficiently special that it could be kept in an internal driver header.
> +#endif
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 039c0d7add1b..ced7486c7f46 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -209,6 +209,11 @@ enum v4l2_colorfx {
> * We reserve 128 controls for this driver.
> */
> #define V4L2_CID_USER_CCS_BASE (V4L2_CID_USER_BASE + 0x10f0)
> +/*
> + * The base for HANTRO driver controls.
> + * We reserve 32 controls for this driver.
> + */
> +#define V4L2_CID_USER_HANTRO_BASE (V4L2_CID_USER_BASE + 0x1170)
>
> /* MPEG-class control IDs */
> /* The MPEG controls are applicable to all codec controls
Thanks,
Ezequiel
