[PATCH v3 3/9] media: hevc: add bounded tile-count helpers

[Benjamin Gaignard]

Le 17/06/2026 à 04:19, Michael Bommarito a écrit :
> The stateless HEVC decoders compute the number of tile columns and rows
> from num_tile_columns_minus1 / num_tile_rows_minus1 and clamp it to the
> column_width_minus1[] / row_height_minus1[] capacity before using it as a
> loop bound. Add shared helpers in a new <media/v4l2-hevc.h> so the rkvdec
> and hantro drivers do not each open-code the min_t() clamp.
>
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Michael Bommarito <michael.bommarito at gmail.com>

Reviewed-by: Benjamin Gaignard <benjamin.gaignard at collabora.com>

> ---
>   include/media/v4l2-hevc.h | 41 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 41 insertions(+)
>   create mode 100644 include/media/v4l2-hevc.h
>
> diff --git a/include/media/v4l2-hevc.h b/include/media/v4l2-hevc.h
> new file mode 100644
> index 0000000000000..973c96be16be4
> --- /dev/null
> +++ b/include/media/v4l2-hevc.h
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Helper functions for HEVC stateless codecs.
> + */
> +
> +#ifndef _MEDIA_V4L2_HEVC_H
> +#define _MEDIA_V4L2_HEVC_H
> +
> +#include <linux/minmax.h>
> +#include <media/v4l2-ctrls.h>
> +
> +/**
> + * v4l2_hevc_pps_num_tile_columns - number of HEVC tile columns, bounded
> + * @pps: the V4L2 HEVC PPS control
> + *
> + * Return the number of tile columns (num_tile_columns_minus1 + 1) clamped to
> + * the capacity of column_width_minus1[]. The control validation already
> + * rejects out-of-range counts; this keeps the consuming drivers bounded too.
> + */
> +static inline unsigned int
> +v4l2_hevc_pps_num_tile_columns(const struct v4l2_ctrl_hevc_pps *pps)
> +{
> +	return min_t(unsigned int, pps->num_tile_columns_minus1 + 1,
> +		     ARRAY_SIZE(pps->column_width_minus1));
> +}
> +
> +/**
> + * v4l2_hevc_pps_num_tile_rows - number of HEVC tile rows, bounded
> + * @pps: the V4L2 HEVC PPS control
> + *
> + * Return the number of tile rows (num_tile_rows_minus1 + 1) clamped to the
> + * capacity of row_height_minus1[].
> + */
> +static inline unsigned int
> +v4l2_hevc_pps_num_tile_rows(const struct v4l2_ctrl_hevc_pps *pps)
> +{
> +	return min_t(unsigned int, pps->num_tile_rows_minus1 + 1,
> +		     ARRAY_SIZE(pps->row_height_minus1));
> +}
> +
> +#endif /* _MEDIA_V4L2_HEVC_H */