[PATCH 6/9] media: cedrus: Add ops structure

Maxime Ripard
2018-06-25T13:29:33Z

Hi!

On Thu, Jun 21, 2018 at 11:49:54AM +0200, Paul Kocialkowski wrote:
> Hi,
>
> On Wed, 2018-06-13 at 16:07 +0200, Maxime Ripard wrote:
> > In order to increase the number of codecs supported, we need to decouple
> > the MPEG2 only code that was there up until now and turn it into something
> > a bit more generic.
> >
> > Do that by introducing an intermediate ops structure that would need to be
> > filled by each supported codec. Start by implementing in that structure the
> > setup and trigger hooks that are currently the only functions being
> > implemented by codecs support.
> >
> > To do so, we need to store the current codec in use, which we do at
> > start_streaming time.
>
> With the comments below taken in account, this is:
>
> Acked-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

Thanks!

> > Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> > ---
> > .../platform/sunxi/cedrus/sunxi_cedrus.c | 2 ++
> > .../sunxi/cedrus/sunxi_cedrus_common.h | 11 +++++++
> > .../platform/sunxi/cedrus/sunxi_cedrus_dec.c | 10 +++---
> > .../sunxi/cedrus/sunxi_cedrus_mpeg2.c | 11 +++++--
> > .../sunxi/cedrus/sunxi_cedrus_mpeg2.h | 33 -------------------
> > .../sunxi/cedrus/sunxi_cedrus_video.c | 17 +++++++++-
> > 6 files changed, 42 insertions(+), 42 deletions(-)
> > delete mode 100644 drivers/media/platform/sunxi/cedrus/sunxi_cedrus_mpeg2.h
> >
> > diff --git a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus.c b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus.c
> > index ccd41d9a3e41..bc80480f5dfd 100644
> > --- a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus.c
> > +++ b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus.c
> > @@ -244,6 +244,8 @@ static int sunxi_cedrus_probe(struct platform_device *pdev)
> > if (ret)
> > return ret;
> >
> > + dev->dec_ops[SUNXI_CEDRUS_CODEC_MPEG2] = &sunxi_cedrus_dec_ops_mpeg2;
> > +
> > ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
> > if (ret)
> > goto unreg_media;
> > diff --git a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> > index a5f83c452006..c2e2c92d103b 100644
> > --- a/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> > +++ b/drivers/media/platform/sunxi/cedrus/sunxi_cedrus_common.h
> > @@ -75,6 +75,7 @@ struct sunxi_cedrus_ctx {
> > struct v4l2_pix_format_mplane src_fmt;
> > struct sunxi_cedrus_fmt *vpu_dst_fmt;
> > struct v4l2_pix_format_mplane dst_fmt;
> > + enum sunxi_cedrus_codec current_codec;
>
> Nit: for consistency with the way things are named, "codec_current"
> probably makes more sense.

I'm not quite sure what you mean by consitency here. This structure
has 5 other variables with two words: vpu_src_fmt, src_fmt,
vpu_dst_fmt, dst_fmt and dst_bufs. codec_current would be going
against the consistency of that structure.

> IMO using the natural English order is fine for temporary variables, but
> less so for variables used in common parts like structures. This allows
> seeing "_" as a logical hierarchical delimiter that automatically makes
> us end up with consistent prefixes that can easily be grepped for and
> derived.
>
> But that's just my 2 cents, it's really not a big deal, especially in
> this case!
>
> > struct v4l2_ctrl_handler hdl;
> > struct v4l2_ctrl *ctrls[SUNXI_CEDRUS_CTRL_MAX];
> > @@ -107,6 +108,14 @@ struct sunxi_cedrus_buffer *vb2_to_cedrus_buffer(const struct vb2_buffer *p)
> > return vb2_v4l2_to_cedrus_buffer(to_vb2_v4l2_buffer(p));
> > }
> >
> > +struct sunxi_cedrus_dec_ops {
> > + void (*setup)(struct sunxi_cedrus_ctx *ctx,
> > + struct sunxi_cedrus_run *run);
> > + void (*trigger)(struct sunxi_cedrus_ctx *ctx);
>
> By the way, are we sure that these functions won't ever fail?
> I think this is the case for MPEG2 (there is virtually nothing to check
> for errors) but perhaps it's different for H264.

It won't fail either, and if we need to change it somewhere down the
line, it's quite easy to do.

Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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