[libcamera-devel] [PATCH] libcamera: Give MappedFrameBuffer its own implementation
Kieran Bingham
kieran.bingham at ideasonboard.com
Fri Aug 6 12:44:15 CEST 2021
Hi Hiro,
On 06/08/2021 11:29, Hirokazu Honda wrote:
> Hi Kieran, thank you for the patch.
>
> On Fri, Aug 6, 2021 at 6:25 PM Kieran Bingham
> <kieran.bingham at ideasonboard.com> wrote:
>>
>> The MappedFrameBuffer is a convenience feature which sits on top of the
>> FrameBuffer and facilitates mapping it to CPU accessible memory with mmap.
>>
>> This implementation is internal and currently sits in the same internal
>> files as the internal FrameBuffer, thus exposing those internals to users
>> of the MappedFramebuffer implementation.
>>
>> Move the MappedFrameBuffer and MappedBuffer implementation to its own
>> implementation files, and fix the sources throughout to use that accordingly.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>> ---
>> include/libcamera/internal/framebuffer.h | 36 ----
>> .../libcamera/internal/mapped_framebuffer.h | 52 ++++++
>> include/libcamera/internal/meson.build | 1 +
>> src/android/camera_buffer.h | 2 +
>> src/android/camera_device.h | 2 -
>> src/android/camera_stream.h | 2 -
>> src/android/jpeg/encoder_libjpeg.cpp | 1 +
>> src/android/jpeg/encoder_libjpeg.h | 1 -
>> src/android/jpeg/post_processor_jpeg.h | 2 -
>> src/android/jpeg/thumbnailer.cpp | 2 +
>> src/android/jpeg/thumbnailer.h | 2 +-
>> src/android/mm/generic_camera_buffer.cpp | 2 +-
>> src/android/post_processor.h | 2 -
>> src/android/yuv/post_processor_yuv.cpp | 1 +
>> src/ipa/ipu3/ipu3.cpp | 2 +-
>> src/ipa/raspberrypi/raspberrypi.cpp | 2 +-
>> src/libcamera/framebuffer.cpp | 145 ---------------
>> src/libcamera/mapped_framebuffer.cpp | 171 ++++++++++++++++++
>> src/libcamera/meson.build | 1 +
>> test/mapped-buffer.cpp | 2 +-
>> 20 files changed, 236 insertions(+), 195 deletions(-)
>> create mode 100644 include/libcamera/internal/mapped_framebuffer.h
>> create mode 100644 src/libcamera/mapped_framebuffer.cpp
>>
>
> I wonder if MappedFrameBuffer is so useful that it should be put in
> libcamera/base.
That's ... almost the partial intention of this.
However - base sits 'underneath' libcamera, and this class requires
FrameBuffer which means it has to go 'on top' of libcamera.
We already extracted a copy of this class to the Intel IPA, so indeed
there is scope for this being used elsewhere - but it needs a somewhat
'new' home which isn't determined yet.
So this is part of that clean up eitherway.
> I found src/cam/frame_sink.cpp does mmap()/munmap, which is what
> MappedFrameBuffer does.
Yes, I wanted that requirement to be abstracted - but it was argued that
MappedFrameBuffer should not form part of the libcamera public API.
But as you've seen - there's a lot of detail to mapping FrameBuffers -
and I don't want every application to have to duplicate all of that - so
theres a potential need for this to live 'somewhere'.
We already envisioned a 'helper' library on top of libcamera - so it's
possible it will move to something like that.
>> diff --git a/include/libcamera/internal/framebuffer.h b/include/libcamera/internal/framebuffer.h
>> index 8c187adf70c7..1352578a6cfb 100644
>> --- a/include/libcamera/internal/framebuffer.h
>> +++ b/include/libcamera/internal/framebuffer.h
>> @@ -7,46 +7,10 @@
>> #ifndef __LIBCAMERA_INTERNAL_FRAMEBUFFER_H__
>> #define __LIBCAMERA_INTERNAL_FRAMEBUFFER_H__
>>
>> -#include <sys/mman.h>
>> -#include <vector>
>> -
>> -#include <libcamera/base/class.h>
>> -#include <libcamera/base/span.h>
>> -
>> #include <libcamera/framebuffer.h>
>>
>> namespace libcamera {
>>
>> -class MappedBuffer
>> -{
>> -public:
>> - using Plane = Span<uint8_t>;
>> -
>> - ~MappedBuffer();
>> -
>> - MappedBuffer(MappedBuffer &&other);
>> - MappedBuffer &operator=(MappedBuffer &&other);
>> -
>> - bool isValid() const { return error_ == 0; }
>> - int error() const { return error_; }
>> - const std::vector<Plane> &maps() const { return maps_; }
>> -
>> -protected:
>> - MappedBuffer();
>> -
>> - int error_;
>> - std::vector<Plane> maps_;
>> -
>> -private:
>> - LIBCAMERA_DISABLE_COPY(MappedBuffer)
>> -};
>> -
>> -class MappedFrameBuffer : public MappedBuffer
>> -{
>> -public:
>> - MappedFrameBuffer(const FrameBuffer *buffer, int flags);
>> -};
>> -
>> class FrameBuffer::Private : public Extensible::Private
>> {
>> LIBCAMERA_DECLARE_PUBLIC(FrameBuffer)
>> diff --git a/include/libcamera/internal/mapped_framebuffer.h b/include/libcamera/internal/mapped_framebuffer.h
>> new file mode 100644
>> index 000000000000..41e587364260
>> --- /dev/null
>> +++ b/include/libcamera/internal/mapped_framebuffer.h
>> @@ -0,0 +1,52 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2021, Google Inc.
>> + *
>> + * mapped_framebuffer.h - Frame buffer memory mapping support
>> + */
>> +#ifndef __LIBCAMERA_INTERNAL_MAPPED_FRAMEBUFFER_H__
>> +#define __LIBCAMERA_INTERNAL_MAPPED_FRAMEBUFFER_H__
>> +
>> +#include <sys/mman.h>
>> +#include <vector>
>> +
>> +#include <libcamera/base/class.h>
>> +#include <libcamera/base/span.h>
>> +
>> +#include <libcamera/framebuffer.h>
>> +
>> +namespace libcamera {
>> +
>> +class MappedBuffer
>> +{
>> +public:
>> + using Plane = Span<uint8_t>;
>> +
>> + ~MappedBuffer();
>> +
>> + MappedBuffer(MappedBuffer &&other);
>> + MappedBuffer &operator=(MappedBuffer &&other);
>> +
>> + bool isValid() const { return error_ == 0; }
>> + int error() const { return error_; }
>> + const std::vector<Plane> &maps() const { return maps_; }
>> +
>> +protected:
>> + MappedBuffer();
>> +
>> + int error_;
>> + std::vector<Plane> maps_;
>> +
>> +private:
>> + LIBCAMERA_DISABLE_COPY(MappedBuffer)
>> +};
>> +
>> +class MappedFrameBuffer : public MappedBuffer
>> +{
>> +public:
>> + MappedFrameBuffer(const FrameBuffer *buffer, int flags);
>> +};
>> +
>> +} /* namespace libcamera */
>> +
>> +#endif /* __LIBCAMERA_INTERNAL_MAPPED_FRAMEBUFFER_H__ */
>> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
>> index dac1a2d36fa8..665fd6de4ed3 100644
>> --- a/include/libcamera/internal/meson.build
>> +++ b/include/libcamera/internal/meson.build
>> @@ -28,6 +28,7 @@ libcamera_internal_headers = files([
>> 'ipa_module.h',
>> 'ipa_proxy.h',
>> 'ipc_unixsocket.h',
>> + 'mapped_framebuffer.h',
>> 'media_device.h',
>> 'media_object.h',
>> 'pipeline_handler.h',
>> diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
>> index 21373fa25bf8..e67cfa2b363e 100644
>> --- a/src/android/camera_buffer.h
>> +++ b/src/android/camera_buffer.h
>> @@ -7,6 +7,8 @@
>> #ifndef __ANDROID_CAMERA_BUFFER_H__
>> #define __ANDROID_CAMERA_BUFFER_H__
>>
>> +#include <sys/mman.h>
>> +
>> #include <hardware/camera3.h>
>>
>> #include <libcamera/base/class.h>
>> diff --git a/src/android/camera_device.h b/src/android/camera_device.h
>> index 089a6204605e..dd9aebba7553 100644
>> --- a/src/android/camera_device.h
>> +++ b/src/android/camera_device.h
>> @@ -24,8 +24,6 @@
>> #include <libcamera/request.h>
>> #include <libcamera/stream.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> -
>> #include "camera_capabilities.h"
>> #include "camera_metadata.h"
>> #include "camera_stream.h"
>> diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
>> index 629d9e00e08d..2dab6c3a37d1 100644
>> --- a/src/android/camera_stream.h
>> +++ b/src/android/camera_stream.h
>> @@ -19,8 +19,6 @@
>> #include <libcamera/geometry.h>
>> #include <libcamera/pixel_format.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> -
>> class CameraDevice;
>> class CameraMetadata;
>> class PostProcessor;
>> diff --git a/src/android/jpeg/encoder_libjpeg.cpp b/src/android/jpeg/encoder_libjpeg.cpp
>> index e6358ca9466f..372018d2207f 100644
>> --- a/src/android/jpeg/encoder_libjpeg.cpp
>> +++ b/src/android/jpeg/encoder_libjpeg.cpp
>> @@ -23,6 +23,7 @@
>> #include <libcamera/pixel_format.h>
>>
>> #include "libcamera/internal/formats.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> using namespace libcamera;
>>
>> diff --git a/src/android/jpeg/encoder_libjpeg.h b/src/android/jpeg/encoder_libjpeg.h
>> index 14bf89223982..61fbd1a69278 100644
>> --- a/src/android/jpeg/encoder_libjpeg.h
>> +++ b/src/android/jpeg/encoder_libjpeg.h
>> @@ -10,7 +10,6 @@
>> #include "encoder.h"
>>
>> #include "libcamera/internal/formats.h"
>> -#include "libcamera/internal/framebuffer.h"
>>
>> #include <jpeglib.h>
>>
>> diff --git a/src/android/jpeg/post_processor_jpeg.h b/src/android/jpeg/post_processor_jpeg.h
>> index 5c399be9eb6a..6fd3102229ab 100644
>> --- a/src/android/jpeg/post_processor_jpeg.h
>> +++ b/src/android/jpeg/post_processor_jpeg.h
>> @@ -13,8 +13,6 @@
>>
>> #include <libcamera/geometry.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> -
>> class CameraDevice;
>>
>> class PostProcessorJpeg : public PostProcessor
>> diff --git a/src/android/jpeg/thumbnailer.cpp b/src/android/jpeg/thumbnailer.cpp
>> index 5cb00744a688..535e2cece914 100644
>> --- a/src/android/jpeg/thumbnailer.cpp
>> +++ b/src/android/jpeg/thumbnailer.cpp
>> @@ -11,6 +11,8 @@
>>
>> #include <libcamera/formats.h>
>>
>> +#include "libcamera/internal/mapped_framebuffer.h"
>> +
>> using namespace libcamera;
>>
>> LOG_DEFINE_CATEGORY(Thumbnailer)
>> diff --git a/src/android/jpeg/thumbnailer.h b/src/android/jpeg/thumbnailer.h
>> index 68cbf74329a9..4d086c4943b0 100644
>> --- a/src/android/jpeg/thumbnailer.h
>> +++ b/src/android/jpeg/thumbnailer.h
>> @@ -7,10 +7,10 @@
>> #ifndef __ANDROID_JPEG_THUMBNAILER_H__
>> #define __ANDROID_JPEG_THUMBNAILER_H__
>>
>> +#include <libcamera/framebuffer.h>
>> #include <libcamera/geometry.h>
>>
>> #include "libcamera/internal/formats.h"
>> -#include "libcamera/internal/framebuffer.h"
>>
>> class Thumbnailer
>> {
>> diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
>> index 2a4b77ea5236..0c8adfd999b9 100644
>> --- a/src/android/mm/generic_camera_buffer.cpp
>> +++ b/src/android/mm/generic_camera_buffer.cpp
>> @@ -11,7 +11,7 @@
>>
>> #include <libcamera/base/log.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> using namespace libcamera;
>>
>> diff --git a/src/android/post_processor.h b/src/android/post_processor.h
>> index 689f85d9d3b8..ab2b2c606fd0 100644
>> --- a/src/android/post_processor.h
>> +++ b/src/android/post_processor.h
>> @@ -10,8 +10,6 @@
>> #include <libcamera/framebuffer.h>
>> #include <libcamera/stream.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> -
>> #include "camera_buffer.h"
>>
>> class CameraMetadata;
>> diff --git a/src/android/yuv/post_processor_yuv.cpp b/src/android/yuv/post_processor_yuv.cpp
>> index 772e805b32cc..509d4244d614 100644
>> --- a/src/android/yuv/post_processor_yuv.cpp
>> +++ b/src/android/yuv/post_processor_yuv.cpp
>> @@ -16,6 +16,7 @@
>> #include <libcamera/pixel_format.h>
>>
>> #include "libcamera/internal/formats.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> using namespace libcamera;
>>
>> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
>> index 71698d36e50f..2647bf2f3b96 100644
>> --- a/src/ipa/ipu3/ipu3.cpp
>> +++ b/src/ipa/ipu3/ipu3.cpp
>> @@ -20,7 +20,7 @@
>> #include <libcamera/ipa/ipu3_ipa_interface.h>
>> #include <libcamera/request.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> #include "ipu3_agc.h"
>> #include "ipu3_awb.h"
>> diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
>> index 48e11c699f29..76f67dd4567a 100644
>> --- a/src/ipa/raspberrypi/raspberrypi.cpp
>> +++ b/src/ipa/raspberrypi/raspberrypi.cpp
>> @@ -28,7 +28,7 @@
>> #include <libcamera/ipa/raspberrypi_ipa_interface.h>
>> #include <libcamera/request.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> #include "agc_algorithm.hpp"
>> #include "agc_status.h"
>> diff --git a/src/libcamera/framebuffer.cpp b/src/libcamera/framebuffer.cpp
>> index a59e93fbdf91..3d98affb20f9 100644
>> --- a/src/libcamera/framebuffer.cpp
>> +++ b/src/libcamera/framebuffer.cpp
>> @@ -251,149 +251,4 @@ Request *FrameBuffer::request() const
>> * indicate that the metadata is invalid.
>> */
>>
>> -/**
>> - * \class MappedBuffer
>> - * \brief Provide an interface to support managing memory mapped buffers
>> - *
>> - * The MappedBuffer interface provides access to a set of MappedPlanes which
>> - * are available for access by the CPU.
>> - *
>> - * This class is not meant to be constructed directly, but instead derived
>> - * classes should be used to implement the correct mapping of a source buffer.
>> - *
>> - * This allows treating CPU accessible memory through a generic interface
>> - * regardless of whether it originates from a libcamera FrameBuffer or other
>> - * source.
>> - */
>> -
>> -/**
>> - * \typedef MappedBuffer::Plane
>> - * \brief A mapped region of memory accessible to the CPU
>> - *
>> - * The MappedBuffer::Plane uses the Span interface to describe the mapped memory
>> - * region.
>> - */
>> -
>> -/**
>> - * \brief Construct an empty MappedBuffer
>> - */
>> -MappedBuffer::MappedBuffer()
>> - : error_(0)
>> -{
>> -}
>> -
>> -/**
>> - * \brief Move constructor, construct the MappedBuffer with the contents of \a
>> - * other using move semantics
>> - * \param[in] other The other MappedBuffer
>> - *
>> - * Moving a MappedBuffer moves the mappings contained in the \a other to the new
>> - * MappedBuffer and invalidates the \a other.
>> - *
>> - * No mappings are unmapped or destroyed in this process.
>> - */
>> -MappedBuffer::MappedBuffer(MappedBuffer &&other)
>> -{
>> - *this = std::move(other);
>> -}
>> -
>> -/**
>> - * \brief Move assignment operator, replace the mappings with those of \a other
>> -* \param[in] other The other MappedBuffer
>> - *
>> - * Moving a MappedBuffer moves the mappings contained in the \a other to the new
>> - * MappedBuffer and invalidates the \a other.
>> - *
>> - * No mappings are unmapped or destroyed in this process.
>> - */
>> -MappedBuffer &MappedBuffer::operator=(MappedBuffer &&other)
>> -{
>> - error_ = other.error_;
>> - maps_ = std::move(other.maps_);
>> - other.error_ = -ENOENT;
>> -
>> - return *this;
>> -}
>> -
>> -MappedBuffer::~MappedBuffer()
>> -{
>> - for (Plane &map : maps_)
>> - munmap(map.data(), map.size());
>> -}
>> -
>> -/**
>> - * \fn MappedBuffer::isValid()
>> - * \brief Check if the MappedBuffer instance is valid
>> - * \return True if the MappedBuffer has valid mappings, false otherwise
>> - */
>> -
>> -/**
>> - * \fn MappedBuffer::error()
>> - * \brief Retrieve the map error status
>> - *
>> - * This function retrieves the error status from the MappedBuffer.
>> - * The error status is a negative number as defined by errno.h. If
>> - * no error occurred, this function returns 0.
>> - *
>> - * \return The map error code
>> - */
>> -
>> -/**
>> - * \fn MappedBuffer::maps()
>> - * \brief Retrieve the mapped planes
>> - *
>> - * This function retrieves the successfully mapped planes stored as a vector
>> - * of Span<uint8_t> to provide access to the mapped memory.
>> - *
>> - * \return A vector of the mapped planes
>> - */
>> -
>> -/**
>> - * \var MappedBuffer::error_
>> - * \brief Stores the error value if present
>> - *
>> - * MappedBuffer derived classes shall set this to a negative value as defined
>> - * by errno.h if an error occured during the mapping process.
>> - */
>> -
>> -/**
>> - * \var MappedBuffer::maps_
>> - * \brief Stores the internal mapped planes
>> - *
>> - * MappedBuffer derived classes shall store the mappings they create in this
>> - * vector which is parsed during destruct to unmap any memory mappings which
>> - * completed successfully.
>> - */
>> -
>> -/**
>> - * \class MappedFrameBuffer
>> - * \brief Map a FrameBuffer using the MappedBuffer interface
>> - */
>> -
>> -/**
>> - * \brief Map all planes of a FrameBuffer
>> - * \param[in] buffer FrameBuffer to be mapped
>> - * \param[in] flags Protection flags to apply to map
>> - *
>> - * Construct an object to map a frame buffer for CPU access.
>> - * The flags are passed directly to mmap and should be either PROT_READ,
>> - * PROT_WRITE, or a bitwise-or combination of both.
>> - */
>> -MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, int flags)
>> -{
>> - maps_.reserve(buffer->planes().size());
>> -
>> - for (const FrameBuffer::Plane &plane : buffer->planes()) {
>> - void *address = mmap(nullptr, plane.length, flags,
>> - MAP_SHARED, plane.fd.fd(), 0);
>> - if (address == MAP_FAILED) {
>> - error_ = -errno;
>> - LOG(Buffer, Error) << "Failed to mmap plane";
>> - break;
>> - }
>> -
>> - maps_.emplace_back(static_cast<uint8_t *>(address), plane.length);
>> - }
>> -}
>> -
>> } /* namespace libcamera */
>> diff --git a/src/libcamera/mapped_framebuffer.cpp b/src/libcamera/mapped_framebuffer.cpp
>> new file mode 100644
>> index 000000000000..0e30fc542154
>> --- /dev/null
>> +++ b/src/libcamera/mapped_framebuffer.cpp
>> @@ -0,0 +1,171 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2021, Google Inc.
>> + *
>> + * mapped_framebuffer.cpp - Mapped Framebuffer support
>> + */
>> +
>> +#include "libcamera/internal/mapped_framebuffer.h"
>> +
>> +#include <errno.h>
>> +#include <string.h>
>> +#include <sys/mman.h>
>> +#include <unistd.h>
>> +
>> +#include <libcamera/base/log.h>
>> +
>> +/**
>> + * \file libcamera/internal/mapped_framebuffer.h
>> + * \brief Frame buffer memory mapping support
>> + */
>> +
>> +namespace libcamera {
>> +
>> +LOG_DECLARE_CATEGORY(Buffer)
>> +
>> +/**
>> + * \class MappedBuffer
>> + * \brief Provide an interface to support managing memory mapped buffers
>> + *
>> + * The MappedBuffer interface provides access to a set of MappedPlanes which
>> + * are available for access by the CPU.
>> + *
>> + * This class is not meant to be constructed directly, but instead derived
>> + * classes should be used to implement the correct mapping of a source buffer.
>> + *
>> + * This allows treating CPU accessible memory through a generic interface
>> + * regardless of whether it originates from a libcamera FrameBuffer or other
>> + * source.
>> + */
>> +
>> +/**
>> + * \typedef MappedBuffer::Plane
>> + * \brief A mapped region of memory accessible to the CPU
>> + *
>> + * The MappedBuffer::Plane uses the Span interface to describe the mapped memory
>> + * region.
>> + */
>> +
>> +/**
>> + * \brief Construct an empty MappedBuffer
>> + */
>> +MappedBuffer::MappedBuffer()
>> + : error_(0)
>> +{
>> +}
>> +
>> +/**
>> + * \brief Move constructor, construct the MappedBuffer with the contents of \a
>> + * other using move semantics
>> + * \param[in] other The other MappedBuffer
>> + *
>> + * Moving a MappedBuffer moves the mappings contained in the \a other to the new
>> + * MappedBuffer and invalidates the \a other.
>> + *
>> + * No mappings are unmapped or destroyed in this process.
>> + */
>> +MappedBuffer::MappedBuffer(MappedBuffer &&other)
>> +{
>> + *this = std::move(other);
>> +}
>> +
>> +/**
>> + * \brief Move assignment operator, replace the mappings with those of \a other
>> +* \param[in] other The other MappedBuffer
>> + *
>> + * Moving a MappedBuffer moves the mappings contained in the \a other to the new
>> + * MappedBuffer and invalidates the \a other.
>> + *
>> + * No mappings are unmapped or destroyed in this process.
>> + */
>> +MappedBuffer &MappedBuffer::operator=(MappedBuffer &&other)
>> +{
>> + error_ = other.error_;
>> + maps_ = std::move(other.maps_);
>> + other.error_ = -ENOENT;
>> +
>> + return *this;
>> +}
>> +
>> +MappedBuffer::~MappedBuffer()
>> +{
>> + for (Plane &map : maps_)
>> + munmap(map.data(), map.size());
>> +}
>> +
>> +/**
>> + * \fn MappedBuffer::isValid()
>> + * \brief Check if the MappedBuffer instance is valid
>> + * \return True if the MappedBuffer has valid mappings, false otherwise
>> + */
>> +
>> +/**
>> + * \fn MappedBuffer::error()
>> + * \brief Retrieve the map error status
>> + *
>> + * This function retrieves the error status from the MappedBuffer.
>> + * The error status is a negative number as defined by errno.h. If
>> + * no error occurred, this function returns 0.
>> + *
>> + * \return The map error code
>> + */
>> +
>> +/**
>> + * \fn MappedBuffer::maps()
>> + * \brief Retrieve the mapped planes
>> + *
>> + * This function retrieves the successfully mapped planes stored as a vector
>> + * of Span<uint8_t> to provide access to the mapped memory.
>> + *
>> + * \return A vector of the mapped planes
>> + */
>> +
>> +/**
>> + * \var MappedBuffer::error_
>> + * \brief Stores the error value if present
>> + *
>> + * MappedBuffer derived classes shall set this to a negative value as defined
>> + * by errno.h if an error occured during the mapping process.
>> + */
>> +
>> +/**
>> + * \var MappedBuffer::maps_
>> + * \brief Stores the internal mapped planes
>> + *
>> + * MappedBuffer derived classes shall store the mappings they create in this
>> + * vector which is parsed during destruct to unmap any memory mappings which
>> + * completed successfully.
>> + */
>> +
>> +/**
>> + * \class MappedFrameBuffer
>> + * \brief Map a FrameBuffer using the MappedBuffer interface
>> + */
>> +
>> +/**
>> + * \brief Map all planes of a FrameBuffer
>> + * \param[in] buffer FrameBuffer to be mapped
>> + * \param[in] flags Protection flags to apply to map
>> + *
>> + * Construct an object to map a frame buffer for CPU access.
>> + * The flags are passed directly to mmap and should be either PROT_READ,
>> + * PROT_WRITE, or a bitwise-or combination of both.
>> + */
>> +MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, int flags)
>> +{
>> + maps_.reserve(buffer->planes().size());
>> +
>> + for (const FrameBuffer::Plane &plane : buffer->planes()) {
>> + void *address = mmap(nullptr, plane.length, flags,
>> + MAP_SHARED, plane.fd.fd(), 0);
>> + if (address == MAP_FAILED) {
>> + error_ = -errno;
>> + LOG(Buffer, Error) << "Failed to mmap plane";
>> + break;
>> + }
>> +
>> + maps_.emplace_back(static_cast<uint8_t *>(address), plane.length);
>> + }
>> +}
>> +
>> +} /* namespace libcamera */
>> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
>> index 4f08580157f9..e9230b983aeb 100644
>> --- a/src/libcamera/meson.build
>> +++ b/src/libcamera/meson.build
>> @@ -28,6 +28,7 @@ libcamera_sources = files([
>> 'ipc_pipe.cpp',
>> 'ipc_pipe_unixsocket.cpp',
>> 'ipc_unixsocket.cpp',
>> + 'mapped_framebuffer.cpp',
>> 'media_device.cpp',
>> 'media_object.cpp',
>> 'pipeline_handler.cpp',
>> diff --git a/test/mapped-buffer.cpp b/test/mapped-buffer.cpp
>> index c9479194cb68..a3d1511b74ce 100644
>> --- a/test/mapped-buffer.cpp
>> +++ b/test/mapped-buffer.cpp
>> @@ -9,7 +9,7 @@
>>
>> #include <libcamera/framebuffer_allocator.h>
>>
>> -#include "libcamera/internal/framebuffer.h"
>> +#include "libcamera/internal/mapped_framebuffer.h"
>>
>> #include "camera_test.h"
>> #include "test.h"
>> --
>> 2.30.2
>>
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