Re: [PATCH v8 14/17] media: hantro: Stop using Hantro dedicated control

From: Hans Verkuil
Date: Tue Jun 14 2022 - 09:59:05 EST

On 6/14/22 10:36, Benjamin Gaignard wrote:
> The number of bits to skip in the slice header can be computed
> in the driver by using sps, pps and decode_params information.
> This allow to remove Hantro dedicated control.

allow -> makes it possible

>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> ---
> drivers/staging/media/hantro/hantro_drv.c | 36 -----------
> .../staging/media/hantro/hantro_g2_hevc_dec.c | 62 ++++++++++++++++++-
> include/media/hevc-ctrls.h | 13 ----
> 3 files changed, 61 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
> index 536c8c374952..5aac3a090480 100644
> --- a/drivers/staging/media/hantro/hantro_drv.c
> +++ b/drivers/staging/media/hantro/hantro_drv.c
> @@ -304,26 +304,6 @@ static int hantro_jpeg_s_ctrl(struct v4l2_ctrl *ctrl)
> return 0;
> }
>
> -static int hantro_hevc_s_ctrl(struct v4l2_ctrl *ctrl)
> -{
> - struct hantro_ctx *ctx;
> -
> - ctx = container_of(ctrl->handler,
> - struct hantro_ctx, ctrl_handler);
> -
> - vpu_debug(1, "s_ctrl: id = %d, val = %d\n", ctrl->id, ctrl->val);
> -
> - switch (ctrl->id) {
> - case V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP:
> - ctx->hevc_dec.ctrls.hevc_hdr_skip_length = ctrl->val;
> - break;
> - default:
> - return -EINVAL;
> - }
> -
> - return 0;
> -}
> -
> static const struct v4l2_ctrl_ops hantro_ctrl_ops = {
> .try_ctrl = hantro_try_ctrl,
> };
> @@ -332,10 +312,6 @@ static const struct v4l2_ctrl_ops hantro_jpeg_ctrl_ops = {
> .s_ctrl = hantro_jpeg_s_ctrl,
> };
>
> -static const struct v4l2_ctrl_ops hantro_hevc_ctrl_ops = {
> - .s_ctrl = hantro_hevc_s_ctrl,
> -};
> -
> #define HANTRO_JPEG_ACTIVE_MARKERS (V4L2_JPEG_ACTIVE_MARKER_APP0 | \
> V4L2_JPEG_ACTIVE_MARKER_COM | \
> V4L2_JPEG_ACTIVE_MARKER_DQT | \
> @@ -487,18 +463,6 @@ static const struct hantro_ctrl controls[] = {
> .cfg = {
> .id = V4L2_CID_STATELESS_HEVC_SCALING_MATRIX,
> },
> - }, {
> - .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,
> - .def = 0,
> - .max = 0x100,
> - .step = 1,
> - .ops = &hantro_hevc_ctrl_ops,
> - },
> }, {
> .codec = HANTRO_VP9_DECODER,
> .cfg = {
> diff --git a/drivers/staging/media/hantro/hantro_g2_hevc_dec.c b/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
> index d28653d04d20..3be8d6e60bf0 100644
> --- a/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
> +++ b/drivers/staging/media/hantro/hantro_g2_hevc_dec.c
> @@ -117,6 +117,66 @@ static void prepare_tile_info_buffer(struct hantro_ctx *ctx)
> vpu_debug(1, "%s: no chroma!\n", __func__);
> }
>
> +static unsigned int ceil_log2(unsigned int v)
> +{
> + /* Compute Ceil(Log2(v))
> + * Derived from branchless code for integer log2(v) from:
> + * <http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog>
> + */
> + unsigned int r, shift;
> +
> + v--;
> + r = (v > 0xFFFF) << 4;
> + v >>= r;
> + shift = (v > 0xFF) << 3;
> + v >>= shift;
> + r |= shift;
> + shift = (v > 0xF) << 2;
> + v >>= shift;
> + r |= shift;
> + shift = (v > 0x3) << 1;
> + v >>= shift;
> + r |= shift;
> + r |= (v >> 1);
> +
> + return r + 1;
> +}

Isn't this identical to fls(v - 1)? See also lib/math/reciprocal_div.c
where this is used.

Regards,

Hans

> +
> +static int compute_header_skip_lenght(struct hantro_ctx *ctx)
> +{
> + const struct hantro_hevc_dec_ctrls *ctrls = &ctx->hevc_dec.ctrls;
> + const struct v4l2_ctrl_hevc_decode_params *decode_params = ctrls->decode_params;
> + const struct v4l2_ctrl_hevc_sps *sps = ctrls->sps;
> + const struct v4l2_ctrl_hevc_pps *pps = ctrls->pps;
> + int skip = 0;
> +
> + if (pps->flags & V4L2_HEVC_PPS_FLAG_OUTPUT_FLAG_PRESENT)
> + /* size of pic_output_flag */
> + skip++;
> +
> + if (sps->flags & V4L2_HEVC_SPS_FLAG_SEPARATE_COLOUR_PLANE)
> + /* size of pic_order_cnt_lsb */
> + skip += 2;
> +
> + if (!(decode_params->flags & V4L2_HEVC_DECODE_PARAM_FLAG_IDR_PIC)) {
> + /* size of pic_order_cnt_lsb */
> + skip += sps->log2_max_pic_order_cnt_lsb_minus4 + 4;
> +
> + /* size of short_term_ref_pic_set_sps_flag */
> + skip++;
> +
> + if (decode_params->short_term_ref_pic_set_size)
> + /* size of st_ref_pic_set( num_short_term_ref_pic_sets ) */
> + skip += decode_params->short_term_ref_pic_set_size;
> + else if (sps->num_short_term_ref_pic_sets > 1)
> + skip += ceil_log2(sps->num_short_term_ref_pic_sets);
> +
> + skip += decode_params->long_term_ref_pic_set_size;
> + }
> +
> + return skip;
> +}
> +
> static void set_params(struct hantro_ctx *ctx)
> {
> const struct hantro_hevc_dec_ctrls *ctrls = &ctx->hevc_dec.ctrls;
> @@ -134,7 +194,7 @@ static void set_params(struct hantro_ctx *ctx)
>
> hantro_reg_write(vpu, &g2_output_8_bits, 0);
>
> - hantro_reg_write(vpu, &g2_hdr_skip_length, ctrls->hevc_hdr_skip_length);
> + hantro_reg_write(vpu, &g2_hdr_skip_length, compute_header_skip_lenght(ctx));
>
> min_log2_cb_size = sps->log2_min_luma_coding_block_size_minus3 + 3;
> max_log2_ctb_size = min_log2_cb_size + sps->log2_diff_max_min_luma_coding_block_size;
> diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> index d6cb3779d190..efc0412ac41e 100644
> --- a/include/media/hevc-ctrls.h
> +++ b/include/media/hevc-ctrls.h
> @@ -467,17 +467,4 @@ struct v4l2_ctrl_hevc_scaling_matrix {
> __u8 scaling_list_dc_coef_32x32[2];
> };
>
> -/* MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */
> -#define V4L2_CID_CODEC_HANTRO_BASE (V4L2_CTRL_CLASS_CODEC | 0x1200)
> -/*
> - * V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP -
> - * the number of data (in bits) to skip in the
> - * slice segment header.
> - * If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
> - * to before syntax element "slice_temporal_mvp_enabled_flag".
> - * If IDR, the skipped bits are just "pic_output_flag"
> - * (separate_colour_plane_flag is not supported).
> - */
> -#define V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (V4L2_CID_CODEC_HANTRO_BASE + 0)
> -
> #endif