[PATCH v4 4/5] libcamera: converter: Add DW100 converter class

[Paul Elder]

On Wed, Jul 03, 2024 at 09:02:56AM +0530, Umang Jain wrote:
> Hi Paul
> 
> On 02/07/24 6:53 pm, Paul Elder wrote:
> > On Thu, Jun 27, 2024 at 07:16:55PM +0530, Umang Jain wrote:
> > > DW100 Dewarp engine is present on i.MX8MP SoC. This patch
> > > provides a converter class (inherited from V4L2M2MConverter).
> > > 
> > > The DW100 converter will be used for scaling capabilites hence, has
> > > a helper to set scaler crop rectangles. Plumbing in the RkISP1
> > > pipeline-handler is done in the subsequent patch.
> > > 
> > > The ConverterDW100 class can be extended later (as additional
> > > development) to support the dewarping by setting a dewarp vertex map.
> > > 
> > > Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> > > ---
> > >   .../internal/converter/converter_dw100.h      | 26 ++++++++
> > >   .../libcamera/internal/converter/meson.build  |  1 +
> > >   src/libcamera/converter/converter_dw100.cpp   | 64 +++++++++++++++++++
> > >   src/libcamera/converter/meson.build           |  1 +
> > >   4 files changed, 92 insertions(+)
> > >   create mode 100644 include/libcamera/internal/converter/converter_dw100.h
> > >   create mode 100644 src/libcamera/converter/converter_dw100.cpp
> > > 
> > > diff --git a/include/libcamera/internal/converter/converter_dw100.h b/include/libcamera/internal/converter/converter_dw100.h
> > > new file mode 100644
> > > index 00000000..dbd39e08
> > > --- /dev/null
> > > +++ b/include/libcamera/internal/converter/converter_dw100.h
> > > @@ -0,0 +1,26 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > > +/*
> > > + * Copyright (C) 2024, Ideas On Board Oy
> > > + *
> > > + * i.MX8MP Dewarp Engine integration
> > > + */
> > > +
> > > +#pragma once
> > > +
> > > +#include "libcamera/internal/converter/converter_v4l2_m2m.h"
> > > +
> > > +namespace libcamera {
> > > +
> > > +class MediaDevice;
> > > +class Rectangle;
> > > +class Stream;
> > > +
> > > +class ConverterDW100 : public V4L2M2MConverter
> > > +{
> > > +public:
> > > +	ConverterDW100(std::shared_ptr<MediaDevice> media);
> > > +
> > > +	int setScalerCrop(const Stream *stream, Rectangle *rect);
> > > +};
> > > +
> > > +} /* namespace libcamera */
> > > diff --git a/include/libcamera/internal/converter/meson.build b/include/libcamera/internal/converter/meson.build
> > > index 891e79e7..85007a4b 100644
> > > --- a/include/libcamera/internal/converter/meson.build
> > > +++ b/include/libcamera/internal/converter/meson.build
> > > @@ -1,5 +1,6 @@
> > >   # SPDX-License-Identifier: CC0-1.0
> > >   libcamera_internal_headers += files([
> > > +    'converter_dw100.h',
> > >       'converter_v4l2_m2m.h',
> > >   ])
> > > diff --git a/src/libcamera/converter/converter_dw100.cpp b/src/libcamera/converter/converter_dw100.cpp
> > > new file mode 100644
> > > index 00000000..78802615
> > > --- /dev/null
> > > +++ b/src/libcamera/converter/converter_dw100.cpp
> > > @@ -0,0 +1,64 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > > +/*
> > > + * Copyright (C) 2024, Ideas On Board Oy
> > > + *
> > > + * i.MX8MP Dewarp Engine integration
> > > + */
> > > +
> > > +#include "libcamera/internal/converter/converter_dw100.h"
> > > +
> > > +#include <libcamera/base/log.h>
> > > +
> > > +#include <libcamera/geometry.h>
> > > +
> > > +#include "libcamera/internal/media_device.h"
> > > +#include "libcamera/internal/v4l2_videodevice.h"
> > > +
> > > +namespace libcamera {
> > > +
> > > +LOG_DECLARE_CATEGORY(Converter)
> > > +
> > > +/**
> > > + * \class libcamera::ConverterDW100
> > > + * \brief The i.MX8MP dewarp converter implements the converter interface based
> > > + * on V4L2 M2M device.
> > > +*/
> > > +
> > > +/**
> > > + * \fn ConverterDW100::ConverterDW100
> > > + * \brief Construct a ConverterDW100 instance
> > > + * \param[in] media The media device implementing the converter
> > > + */
> > > +ConverterDW100::ConverterDW100(std::shared_ptr<MediaDevice> media)
> > > +	: V4L2M2MConverter(media.get(), Feature::Crop)
> > > +{
> > > +}
> > > +
> > > +/**
> > > + * \brief Set the scaler crop rectangle \a rect on \a stream
> > > + * \param[in] stream Pointer to output stream
> > > + * \param[inout] rect The selection rectangle to be applied
> > rect doesn't seem to be used as an output parameter?
> > 
> > > + *
> > > + * \return 0 on success or a negative error code otherwise
> > > + */
> > > +int ConverterDW100::setScalerCrop(const Stream *stream, Rectangle *rect)
> > > +{
> > > +	Rectangle apply = *rect;
> > This dereference scares me but I see you want to use it as an output
> > parameter (I assume to report the rectangle that was actually set).
> 
> This setScalerCrop()  something can be dropped, to directly call setCrop()
> of the converter by the consumer.

Oh right yeah that's true. The caller would be responsible for checking
the capability.


Paul

> 
> But first, I want to just check what should be the handling of the below
> \todo w.r.t to applied rectangles, hence I kept a additional wrapper around
> setCrop() for now.
> 
> > 
> > > +	int ret;
> > > +
> > > +	ret = setCrop(stream, &apply);
> > > +	if (ret < 0)
> > > +		LOG(Converter, Error) << "Failed to set scaler crop "
> > > +				      << apply.toString() << " on dewarper "
> > > +				      << strerror(-ret);
> > Can't we just return here?
> > 
> > > +
> > > +	if (*rect != apply) {
> > > +		/* \todo This case needs proper after handling. */
> > I think it's ok to just return the scaler crop that was able to be set.
> 
> I think that too and report that as metadata.
> > 
> > 
> > Paul
> > 
> > > +		LOG(Converter, Warning) << "Applied rectangle " << apply.toString()
> > > +					<< " differs from requested " << rect->toString();
> > > +	}
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +} /* namespace libcamera */
> > > diff --git a/src/libcamera/converter/meson.build b/src/libcamera/converter/meson.build
> > > index 2aa72fe4..175581b8 100644
> > > --- a/src/libcamera/converter/meson.build
> > > +++ b/src/libcamera/converter/meson.build
> > > @@ -1,5 +1,6 @@
> > >   # SPDX-License-Identifier: CC0-1.0
> > >   libcamera_sources += files([
> > > +        'converter_dw100.cpp',
> > >           'converter_v4l2_m2m.cpp'
> > >   ])
> > > -- 
> > > 2.44.0
> > > 
>