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Message-ID: <65c2e2805b40b1d88ac9f380bda53c085bf612e6.camel@collabora.com>
Subject: Re: [PATCH v8 14/17] media: hantro: Stop using Hantro dedicated
 control
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        Hans Verkuil <hverkuil@xs4all.nl>, 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, 21 Jun 2022 10:50:47 -0400
In-Reply-To: <f6c636b6-f379-650a-cc7c-6f1e8b014455@collabora.com>
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>
         <ac31307f9186fc851f76889a66ffb007de88fa15.camel@collabora.com>
         <f6c636b6-f379-650a-cc7c-6f1e8b014455@collabora.com>
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Le mardi 14 juin 2022 =C3=A0 18:46 +0200, Benjamin Gaignard a =C3=A9crit=C2=
=A0:
> Le 14/06/2022 =C3=A0 18:23, Nicolas Dufresne a =C3=A9crit=C2=A0:
> > Le mardi 14 juin 2022 =C3=A0 17:47 +0200, Hans Verkuil a =C3=A9crit=C2=
=A0:
> > > 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.
> > > > > allow -> makes it possible
> > > > >=20
> > > > > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.c=
om>
> > > > > > ---
> > > > > >   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/driver=
s/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;
> > > > > >   }
> > > > > >  =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, ctr=
l->val);
> > > > > > -
> > > > > > -	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_j=
peg_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_A=
PP0 | \
> > > > > >   					 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/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(struc=
t hantro_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#Integ=
erLog>
> > > > > > +	 */
> > > > > > +	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;
> > > > > > +}
> > > > > Isn't this identical to fls(v - 1)? See also lib/math/reciprocal_=
div.c
> > > > > where this is used.
> > > > Thanks for pointing this out, I was wondering if there was an equiv=
alent, and
> > > > never knew there was a relation between log2() and the "last set bi=
t". Not sure
> > > > about the -1 here though, can you extend ?
> > > Based on how lib/math/reciprocal_div.c did it. Also, the ceil_log2 fu=
nction
> > > starts with v--, while fls doesn't. That said, it's wise to verify th=
at that
> > > is correct.
> > Just for the reference, from lib/math/reciprocal_div.c:
> >=20
> > 	/* ceil(log2(d)) */
> > 	l =3D fls(d - 1);
> >=20
> > Perhaps fls() return position starting from 1 rather then 0 ?
>=20
> I have compare the results of ceil_log2(d) vs fls(d-1)
> for values between 2 (because sps->num_short_term_ref_pic_sets > 1) and 1=
6 (the maximum number of frames)
> they are always the same so I will remove ceil_log2() and use fls().

I've also check on my side few samples, and it indeed seems to be exactly t=
he
same.

>=20
> Regards,
> Benjamin
>=20
> >=20
> > Nicolas
> >=20
> > > Regards,
> > >=20
> > > 	Hans
> > >=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.=
ctrls;
> > > > > > +	const struct v4l2_ctrl_hevc_decode_params *decode_params =3D =
ctrls->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=
.ctrls;
> > > > > > @@ -134,7 +194,7 @@ static void set_params(struct hantro_ctx *c=
tx)
> > > > > >  =20
> > > > > >   	hantro_reg_write(vpu, &g2_output_8_bits, 0);
> > > > > >  =20
> > > > > > -	hantro_reg_write(vpu, &g2_hdr_skip_length, ctrls->hevc_hdr_sk=
ip_length);
> > > > > > +	hantro_reg_write(vpu, &g2_hdr_skip_length, compute_header_ski=
p_lenght(ctx));
> > > > > >  =20
> > > > > >   	min_log2_cb_size =3D sps->log2_min_luma_coding_block_size_mi=
nus3 + 3;
> > > > > >   	max_log2_ctb_size =3D 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-ct=
rls.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 de=
fined 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