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Message-ID: <ac31307f9186fc851f76889a66ffb007de88fa15.camel@collabora.com>
Subject: Re: [PATCH v8 14/17] media: hantro: Stop using Hantro dedicated
 control
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        mchehab@kernel.org, ezequiel@vanguardiasur.com.ar,
        p.zabel@pengutronix.de, gregkh@linuxfoundation.org,
        mripard@kernel.org, paul.kocialkowski@bootlin.com, wens@csie.org,
        jernej.skrabec@gmail.com, samuel@sholland.org,
        andrzej.p@collabora.com
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        kernel@collabora.com
Date:   Tue, 14 Jun 2022 12:23:47 -0400
In-Reply-To: <c5c6903d-ec7d-6218-35d3-2ac6caa9d2c5@xs4all.nl>
References: <20220614083614.240641-1-benjamin.gaignard@collabora.com>
         <20220614083614.240641-15-benjamin.gaignard@collabora.com>
         <b244e86d-06de-7423-d0df-e77485ce4c87@xs4all.nl>
         <958ab30f9cfbb14e4a7ea55826064e6a20d5ffd2.camel@collabora.com>
         <c5c6903d-ec7d-6218-35d3-2ac6caa9d2c5@xs4all.nl>
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Le mardi 14 juin 2022 =C3=A0 17:47 +0200, Hans Verkuil a =C3=A9crit=C2=A0:
>=20
> On 6/14/22 17:43, Nicolas Dufresne wrote:
> > Le mardi 14 juin 2022 =C3=A0 15:58 +0200, Hans Verkuil a =C3=A9crit=C2=
=A0:
> > > 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.
> > >=20
> > > allow -> makes it possible
> > >=20
> > > >=20
> > > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> > > > ---
> > > >  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(-)
> > > >=20
> > > > diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/st=
aging/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;
> > > >  }
> > > > =20
> > > > -static int hantro_hevc_s_ctrl(struct v4l2_ctrl *ctrl)
> > > > -{
> > > > -	struct hantro_ctx *ctx;
> > > > -
> > > > -	ctx =3D container_of(ctrl->handler,
> > > > -			   struct hantro_ctx, ctrl_handler);
> > > > -
> > > > -	vpu_debug(1, "s_ctrl: id =3D %d, val =3D %d\n", ctrl->id, ctrl->v=
al);
> > > > -
> > > > -	switch (ctrl->id) {
> > > > -	case V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP:
> > > > -		ctx->hevc_dec.ctrls.hevc_hdr_skip_length =3D ctrl->val;
> > > > -		break;
> > > > -	default:
> > > > -		return -EINVAL;
> > > > -	}
> > > > -
> > > > -	return 0;
> > > > -}
> > > > -
> > > >  static const struct v4l2_ctrl_ops hantro_ctrl_ops =3D {
> > > >  	.try_ctrl =3D hantro_try_ctrl,
> > > >  };
> > > > @@ -332,10 +312,6 @@ static const struct v4l2_ctrl_ops hantro_jpeg_=
ctrl_ops =3D {
> > > >  	.s_ctrl =3D hantro_jpeg_s_ctrl,
> > > >  };
> > > > =20
> > > > -static const struct v4l2_ctrl_ops hantro_hevc_ctrl_ops =3D {
> > > > -	.s_ctrl =3D 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[] =3D=
 {
> > > >  		.cfg =3D {
> > > >  			.id =3D V4L2_CID_STATELESS_HEVC_SCALING_MATRIX,
> > > >  		},
> > > > -	}, {
> > > > -		.codec =3D HANTRO_HEVC_DECODER,
> > > > -		.cfg =3D {
> > > > -			.id =3D V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP,
> > > > -			.name =3D "Hantro HEVC slice header skip bytes",
> > > > -			.type =3D V4L2_CTRL_TYPE_INTEGER,
> > > > -			.min =3D 0,
> > > > -			.def =3D 0,
> > > > -			.max =3D 0x100,
> > > > -			.step =3D 1,
> > > > -			.ops =3D &hantro_hevc_ctrl_ops,
> > > > -		},
> > > >  	}, {
> > > >  		.codec =3D HANTRO_VP9_DECODER,
> > > >  		.cfg =3D {
> > > > diff --git a/drivers/staging/media/hantro/hantro_g2_hevc_dec.c b/dr=
ivers/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 ha=
ntro_ctx *ctx)
> > > >  		vpu_debug(1, "%s: no chroma!\n", __func__);
> > > >  }
> > > > =20
> > > > +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#IntegerLo=
g>
> > > > +	 */
> > > > +	unsigned int r, shift;
> > > > +
> > > > +	v--;
> > > > +	r =3D (v > 0xFFFF) << 4;
> > > > +	v >>=3D r;
> > > > +	shift =3D (v > 0xFF) << 3;
> > > > +	v >>=3D shift;
> > > > +	r |=3D shift;
> > > > +	shift =3D (v > 0xF) << 2;
> > > > +	v >>=3D shift;
> > > > +	r |=3D shift;
> > > > +	shift =3D (v > 0x3) << 1;
> > > > +	v >>=3D shift;
> > > > +	r |=3D shift;
> > > > +	r |=3D (v >> 1);
> > > > +
> > > > +	return r + 1;
> > > > +}
> > >=20
> > > Isn't this identical to fls(v - 1)? See also lib/math/reciprocal_div.=
c
> > > where this is used.
> >=20
> > Thanks for pointing this out, I was wondering if there was an equivalen=
t, and
> > never knew there was a relation between log2() and the "last set bit". =
Not sure
> > about the -1 here though, can you extend ?
>=20
> Based on how lib/math/reciprocal_div.c did it. Also, the ceil_log2 functi=
on
> starts with v--, while fls doesn't. That said, it's wise to verify that t=
hat
> is correct.

Just for the reference, from lib/math/reciprocal_div.c:

	/* ceil(log2(d)) */
	l =3D fls(d - 1);

Perhaps fls() return position starting from 1 rather then 0 ?

Nicolas

>=20
> Regards,
>=20
> 	Hans
>=20
> >=20
> > >=20
> > > Regards,
> > >=20
> > > 	Hans
> > >=20
> > > > +
> > > > +static int compute_header_skip_lenght(struct hantro_ctx *ctx)
> > > > +{
> > > > +	const struct hantro_hevc_dec_ctrls *ctrls =3D &ctx->hevc_dec.ctrl=
s;
> > > > +	const struct v4l2_ctrl_hevc_decode_params *decode_params =3D ctrl=
s->decode_params;
> > > > +	const struct v4l2_ctrl_hevc_sps *sps =3D ctrls->sps;
> > > > +	const struct v4l2_ctrl_hevc_pps *pps =3D ctrls->pps;
> > > > +	int skip =3D 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 +=3D 2;
> > > > +
> > > > +	if (!(decode_params->flags & V4L2_HEVC_DECODE_PARAM_FLAG_IDR_PIC)=
) {
> > > > +		/* size of pic_order_cnt_lsb */
> > > > +		skip +=3D 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 +=3D decode_params->short_term_ref_pic_set_size;
> > > > +		else if (sps->num_short_term_ref_pic_sets > 1)
> > > > +			skip +=3D ceil_log2(sps->num_short_term_ref_pic_sets);
> > > > +
> > > > +		skip +=3D 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 =3D &ctx->hevc_dec.ctrl=
s;
> > > > @@ -134,7 +194,7 @@ static void set_params(struct hantro_ctx *ctx)
> > > > =20
> > > >  	hantro_reg_write(vpu, &g2_output_8_bits, 0);
> > > > =20
> > > > -	hantro_reg_write(vpu, &g2_hdr_skip_length, ctrls->hevc_hdr_skip_l=
ength);
> > > > +	hantro_reg_write(vpu, &g2_hdr_skip_length, compute_header_skip_le=
nght(ctx));
> > > > =20
> > > >  	min_log2_cb_size =3D sps->log2_min_luma_coding_block_size_minus3 =
+ 3;
> > > >  	max_log2_ctb_size =3D min_log2_cb_size + sps->log2_diff_max_min_l=
uma_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];
> > > >  };
> > > > =20
> > > > -/*  MPEG-class control IDs specific to the Hantro driver as define=
d by V4L2 */
> > > > -#define V4L2_CID_CODEC_HANTRO_BASE				(V4L2_CTRL_CLASS_CODEC | 0x1=
200)
> > > > -/*
> > > > - * 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_HAN=
TRO_BASE + 0)
> > > > -
> > > >  #endif
> > >=20
> >=20