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

[Umang Jain]

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.

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
>>