[v3,24/39] libcamera: software_isp: gbm: Add in a GBM helper class for GPU surface access

24669 diff mbox series

A helper class to interact with GBM. This will allow us to specify the
internal storage format of the CPU when making a texture for the Debayer
vertext/fragment shaders and thus ensure we receive an uncompressed and
untiled output buffer.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
 include/libcamera/internal/gbm.h       | 43 ++++++++++++++++++
 include/libcamera/internal/meson.build |  1 +
 src/libcamera/gbm.cpp                  | 61 ++++++++++++++++++++++++++
 src/libcamera/meson.build              | 11 +++++
 4 files changed, 116 insertions(+)
 create mode 100644 include/libcamera/internal/gbm.h
 create mode 100644 src/libcamera/gbm.cpp

Hi Bryan,

see
https://lists.libcamera.org/pipermail/libcamera-devel/2025-June/050901.html

Bryan O'Donoghue <bryan.odonoghue@linaro.org> writes:

> A helper class to interact with GBM. This will allow us to specify the
> internal storage format of the CPU when making a texture for the Debayer
> vertext/fragment shaders and thus ensure we receive an uncompressed and
> untiled output buffer.
>
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> ---
>  include/libcamera/internal/gbm.h | 43 ++++++++++++++++++
>  include/libcamera/internal/meson.build |  1 +
>  src/libcamera/gbm.cpp | 61 ++++++++++++++++++++++++++
>  src/libcamera/meson.build              | 11 +++++
>  4 files changed, 116 insertions(+)
>  create mode 100644 include/libcamera/internal/gbm.h
>  create mode 100644 src/libcamera/gbm.cpp
>
> diff --git a/include/libcamera/internal/gbm.h b/include/libcamera/internal/gbm.h
> new file mode 100644
> index 00000000..41b5e00f
> --- /dev/null
> +++ b/include/libcamera/internal/gbm.h
> @@ -0,0 +1,43 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Linaro Ltd.
> + *
> + * Authors:
> + * Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> + *
> + * gbm.h - Helper class for managing GBM interactions.
> + */
> +
> +#pragma once
> +
> +#include <gbm.h>
> +
> +#include <libcamera/base/log.h>
> +
> +#include <libcamera/formats.h>
> +
> +namespace libcamera {
> +
> +LOG_DECLARE_CATEGORY(GBM)
> +
> +/**
> + * \brief Helper class for managing GBM interactions
> + *
> + */
> +class GBM
> +{
> +public:
> +	GBM();
> +	~GBM();
> +
> +	int createDevice();
> +	struct gbm_device *getDevice() { return gbm_device_; }
> +	PixelFormat getPixelFormat() { return format_; }
> +
> +private:
> +	int fd_;
> +	struct gbm_device *gbm_device_;
> +	PixelFormat format_;
> +};
> +
> +} // namespace libcamera
> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
> index ecb7c9fa..01a36595 100644
> --- a/include/libcamera/internal/meson.build
> +++ b/include/libcamera/internal/meson.build
> @@ -24,6 +24,7 @@ libcamera_internal_headers = files([
>      'dma_buf_allocator.h',
>      'formats.h',
>      'framebuffer.h',
> +    'gbm.h',
>      'global_configuration.h',
>      'ipa_data_serializer.h',
>      'ipa_manager.h',
> diff --git a/src/libcamera/gbm.cpp b/src/libcamera/gbm.cpp
> new file mode 100644
> index 00000000..caf9ca1c
> --- /dev/null
> +++ b/src/libcamera/gbm.cpp
> @@ -0,0 +1,61 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Linaro Ltd.
> + *
> + * Authors:
> + * Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> + *
> + * egl.cpp - Helper class for managing GBM interactions.
> + */
> +
> +#include "libcamera/internal/gbm.h"
> +
> +#include <fcntl.h>
> +#include <sys/ioctl.h>
> +#include <sys/mman.h>
> +#include <unistd.h>
> +
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +
> +namespace libcamera {
> +
> +LOG_DEFINE_CATEGORY(GBM)
> +
> +GBM::GBM()
> +{
> +	fd_ = 0;
> +}
> +
> +GBM::~GBM()
> +{
> +	if (gbm_device_)
> +		gbm_device_destroy(gbm_device_);
> +
> +	if (fd_ >= 0)
> +		close(fd_);
> +}
> +
> +int GBM::createDevice()
> +{
> +	const char *dri_node = "/dev/dri/renderD128"; //TODO: get from an env or config setting
> +
> +	fd_ = open(dri_node, O_RDWR | O_CLOEXEC);
> +	if (fd_ < 0) {
> +		LOG(GBM, Error) << "Open " << dri_node << " fail " << fd_;
> +		return fd_;
> +	}
> +
> +	gbm_device_ = gbm_create_device(fd_);
> +	if (!gbm_device_) {
> +		LOG(GBM, Error) << "gbm_crate_device fail";
> +		goto fail;
> +	}
> +
> +	format_ = libcamera::formats::ARGB8888;
> +
> +	return 0;
> +fail:
> +	return -ENODEV;
> +}
> +} //namespace libcamera
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 5b9b86f2..fe60c875 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -69,6 +69,16 @@ libcamera_deps = []
>  libatomic = cc.find_library('atomic', required : false)
>  libthreads = dependency('threads')
>  
> +libgbm = cc.find_library('gbm', required: false)
> +gbm_works = cc.check_header('gbm.h', required: false)
> +
> +if libgbm.found() and gbm_works
> +    config_h.set('HAVE_GBM', 1)
> +    libcamera_internal_sources += files([
> +        'gbm.cpp',
> +    ])
> +endif
> +
>  subdir('base')
>  subdir('converter')
>  subdir('ipa')
> @@ -176,6 +186,7 @@ libcamera_deps += [
>      libcamera_base_private,
>      libcrypto,
>      libdl,
> +    libgbm,
>      liblttng,
>      libudev,
>      libyaml,