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From:   Tomasz Figa <tfiga@chromium.org>
Date:   Fri, 8 May 2020 18:56:18 +0200
Message-ID: <CAAFQd5C3MpWqRRMGQJTW8rNz65T2CRYj6yFa56mJWR+DFqrFzg@mail.gmail.com>
Subject: Re: [PATCH v3 3/3] media: rkvdec: Add the VP9 backend
To:     Ezequiel Garcia <ezequiel@collabora.com>
Cc:     Hans Verkuil <hverkuil@xs4all.nl>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kernel@collabora.com, Jonas Karlman <jonas@kwiboo.se>,
        Heiko Stuebner <heiko@sntech.de>,
        Alexandre Courbot <acourbot@chromium.org>,
        Jeffrey Kardatzke <jkardatzke@chromium.org>,
        Gustavo Padovan <gustavo.padovan@collabora.com>,
        Boris Brezillon <boris.brezillon@collabora.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On Fri, May 8, 2020 at 6:26 PM Ezequiel Garcia <ezequiel@collabora.com> wrote:
>
> On Fri, 2020-05-08 at 12:34 +0200, Hans Verkuil wrote:
> > On 05/05/2020 15:41, Ezequiel Garcia wrote:
> > > From: Boris Brezillon <boris.brezillon@collabora.com>
> > >
> > > The Rockchip VDEC supports VP9 profile 0 up to 4096x2304@30fps. Add
> > > a backend for this new format.
> > >
> > > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> > > Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> > > ---
> > >  drivers/staging/media/rkvdec/Makefile     |    2 +-
> > >  drivers/staging/media/rkvdec/rkvdec-vp9.c | 1577 +++++++++++++++++++++
> > >  drivers/staging/media/rkvdec/rkvdec.c     |   56 +-
> > >  drivers/staging/media/rkvdec/rkvdec.h     |    6 +
> > >  4 files changed, 1637 insertions(+), 4 deletions(-)
> > >  create mode 100644 drivers/staging/media/rkvdec/rkvdec-vp9.c
> > >
> > > diff --git a/drivers/staging/media/rkvdec/Makefile b/drivers/staging/media/rkvdec/Makefile
> > > index c08fed0a39f9..cb86b429cfaa 100644
> > > --- a/drivers/staging/media/rkvdec/Makefile
> > > +++ b/drivers/staging/media/rkvdec/Makefile
> > > @@ -1,3 +1,3 @@
> > >  obj-$(CONFIG_VIDEO_ROCKCHIP_VDEC) += rockchip-vdec.o
> > >
> > > -rockchip-vdec-y += rkvdec.o rkvdec-h264.o
> > > +rockchip-vdec-y += rkvdec.o rkvdec-h264.o rkvdec-vp9.o
> > > diff --git a/drivers/staging/media/rkvdec/rkvdec-vp9.c b/drivers/staging/media/rkvdec/rkvdec-vp9.c
> > > new file mode 100644
> > > index 000000000000..37d0ea4e3570
> > > --- /dev/null
> > > +++ b/drivers/staging/media/rkvdec/rkvdec-vp9.c
> > > @@ -0,0 +1,1577 @@
> >
> > <snip>
> >
> > > +static void init_inter_probs(struct rkvdec_ctx *ctx,
> > > +                        const struct rkvdec_vp9_run *run)
> > > +{
> > > +   const struct v4l2_ctrl_vp9_frame_decode_params *dec_params;
> > > +   struct rkvdec_vp9_ctx *vp9_ctx = ctx->priv;
> > > +   struct rkvdec_vp9_priv_tbl *tbl = vp9_ctx->priv_tbl.cpu;
> > > +   struct rkvdec_vp9_inter_frame_probs *rkprobs;
> > > +   const struct v4l2_vp9_probabilities *probs;
> > > +   unsigned int i, j, k;
> > > +
> > > +   rkprobs = &tbl->probs.inter;
> > > +   dec_params = run->decode_params;
> > > +   probs = &dec_params->probs;
> > > +
> > > +   /*
> > > +    * inter probs
> > > +    * 151 x 128 bits, aligned to 152 x 128 bits
> > > +    * inter only
> > > +    * intra_y_mode & inter_block info 6 x 128 bits
> > > +    */
> > > +
> > > +   memcpy(rkprobs->y_mode, probs->y_mode, sizeof(rkprobs->y_mode));
> > > +   memcpy(rkprobs->comp_mode, probs->comp_mode,
> > > +          sizeof(rkprobs->comp_mode));
> > > +   memcpy(rkprobs->comp_ref, probs->comp_ref,
> > > +          sizeof(rkprobs->comp_ref));
> > > +   memcpy(rkprobs->single_ref, probs->single_ref,
> > > +          sizeof(rkprobs->single_ref));
> > > +   memcpy(rkprobs->inter_mode, probs->inter_mode,
> > > +          sizeof(rkprobs->inter_mode));
> > > +   memcpy(rkprobs->interp_filter, probs->interp_filter,
> > > +          sizeof(rkprobs->interp_filter));
> > > +
> > > +   /* 128 x 128 bits coeff related */
> > > +   for (i = 0; i < ARRAY_SIZE(probs->coef); i++) {
> > > +           for (j = 0; j < ARRAY_SIZE(probs->coef[0]); j++) {
> > > +                   for (k = 0; k < ARRAY_SIZE(probs->coef[0][0]); k++)
> > > +                           write_coeff_plane(probs->coef[i][j][k],
> > > +                                             rkprobs->coef[k][i][j]);
> > > +           }
> > > +   }
> > > +
> > > +   /* intra uv mode 6 x 128 */
> > > +   memcpy(rkprobs->uv_mode_0_2, &probs->uv_mode[0],
> > > +          sizeof(rkprobs->uv_mode_0_2));
> > > +   memcpy(rkprobs->uv_mode_3_5, &probs->uv_mode[3],
> > > +          sizeof(rkprobs->uv_mode_3_5));
> > > +   memcpy(rkprobs->uv_mode_6_8, &probs->uv_mode[6],
> > > +          sizeof(rkprobs->uv_mode_6_8));
> > > +   memcpy(rkprobs->uv_mode_9, &probs->uv_mode[9],
> > > +          sizeof(rkprobs->uv_mode_9));
> > > +
> > > +   /* mv related 6 x 128 */
> > > +   memcpy(rkprobs->mv.joint, probs->mv.joint,
> > > +          sizeof(rkprobs->mv.joint));
> > > +   memcpy(rkprobs->mv.sign, probs->mv.sign,
> > > +          sizeof(rkprobs->mv.sign));
> > > +   memcpy(rkprobs->mv.class, probs->mv.class,
> > > +          sizeof(rkprobs->mv.class));
> > > +   memcpy(rkprobs->mv.class0_bit, probs->mv.class0_bit,
> > > +          sizeof(rkprobs->mv.class0_bit));
> > > +   memcpy(rkprobs->mv.bits, probs->mv.bits,
> > > +          sizeof(rkprobs->mv.bits));
> > > +   memcpy(rkprobs->mv.class0_fr, probs->mv.class0_fr,
> > > +          sizeof(rkprobs->mv.class0_fr));
> > > +   memcpy(rkprobs->mv.fr, probs->mv.fr,
> > > +          sizeof(rkprobs->mv.fr));
> > > +   memcpy(rkprobs->mv.class0_hp, probs->mv.class0_hp,
> > > +          sizeof(rkprobs->mv.class0_hp));
> > > +   memcpy(rkprobs->mv.hp, probs->mv.hp,
> > > +          sizeof(rkprobs->mv.hp));
> >
> > Can't you just do: 'rkprobs->mv = probs->mv'?
> >
>
> I think I'd like to keep this as-is.
>
> Having the memcpy makes it explicit that we are copying
> these structs around. While the assignment would
> bring type checking, it can be misleading for readers.

On the other hand, it's not obvious from the code that all fields of
the structure are copied. Perhaps memcpy(&rkprobs->mv, &probs->mv,
sizeof(rkprobs->mv)) would be a good compromise?