From eb4030f6c07174a520be1ebd73628e9ae4789569 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Niklas=20S=C3=B6derlund?= Date: Sun, 27 Oct 2019 22:10:25 +0100 Subject: libcamera: allocator: Add FrameBufferAllocator to help applications allocate buffers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The FrameBuffer interface is based on the idea that all buffers are allocated externally to libcamera and are only used by it. This is meant to create a simpler API centered around usage of buffers, regardless of where they come from. Linux however lacks a centralized allocator at the moment, and not all users of libcamera are expected to use another device that could provide suitable buffers for the camera. This patch thus adds a helper class to allocate buffers internally in libcamera, in a way that matches the needs of the FrameBuffer-based API. Signed-off-by: Niklas Söderlund Reviewed-by: Laurent Pinchart --- include/libcamera/camera.h | 5 + include/libcamera/framebuffer_allocator.h | 45 +++++++ include/libcamera/meson.build | 1 + src/libcamera/camera.cpp | 19 ++- src/libcamera/framebuffer_allocator.cpp | 216 ++++++++++++++++++++++++++++++ src/libcamera/meson.build | 1 + 6 files changed, 286 insertions(+), 1 deletion(-) create mode 100644 include/libcamera/framebuffer_allocator.h create mode 100644 src/libcamera/framebuffer_allocator.cpp diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h index ef6a37bb..2fd5870b 100644 --- a/include/libcamera/camera.h +++ b/include/libcamera/camera.h @@ -20,6 +20,7 @@ namespace libcamera { class Buffer; +class FrameBufferAllocator; class PipelineHandler; class Request; @@ -126,6 +127,10 @@ private: bool disconnected_; State state_; + + /* Needed to update allocator_ and to read state_ and activeStreams_. */ + friend class FrameBufferAllocator; + FrameBufferAllocator *allocator_; }; } /* namespace libcamera */ diff --git a/include/libcamera/framebuffer_allocator.h b/include/libcamera/framebuffer_allocator.h new file mode 100644 index 00000000..42812253 --- /dev/null +++ b/include/libcamera/framebuffer_allocator.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * framebuffer_allocator.h - FrameBuffer allocator + */ +#ifndef __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__ +#define __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__ + +#include +#include +#include + +namespace libcamera { + +class Camera; +class FrameBuffer; +class Stream; + +class FrameBufferAllocator +{ +public: + static FrameBufferAllocator *create(std::shared_ptr camera); + + FrameBufferAllocator(const Camera &) = delete; + FrameBufferAllocator &operator=(const Camera &) = delete; + + ~FrameBufferAllocator(); + + int allocate(Stream *stream); + int free(Stream *stream); + + bool allocated() const { return !buffers_.empty(); } + const std::vector> &buffers(Stream *stream) const; + +private: + FrameBufferAllocator(std::shared_ptr camera); + + std::shared_ptr camera_; + std::map>> buffers_; +}; + +} /* namespace libcamera */ + +#endif /* __LIBCAMERA_FRAMEBUFFER_ALLOCATOR_H__ */ diff --git a/include/libcamera/meson.build b/include/libcamera/meson.build index 543e6773..8db217bb 100644 --- a/include/libcamera/meson.build +++ b/include/libcamera/meson.build @@ -7,6 +7,7 @@ libcamera_api = files([ 'event_dispatcher.h', 'event_notifier.h', 'file_descriptor.h', + 'framebuffer_allocator.h', 'geometry.h', 'logging.h', 'object.h', diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp index 5d294b10..20340167 100644 --- a/src/libcamera/camera.cpp +++ b/src/libcamera/camera.cpp @@ -9,6 +9,7 @@ #include +#include #include #include @@ -405,7 +406,7 @@ const std::string &Camera::name() const Camera::Camera(PipelineHandler *pipe, const std::string &name) : pipe_(pipe->shared_from_this()), name_(name), disconnected_(false), - state_(CameraAvailable) + state_(CameraAvailable), allocator_(nullptr) { } @@ -541,6 +542,16 @@ int Camera::release() if (!stateBetween(CameraAvailable, CameraConfigured)) return -EBUSY; + if (allocator_) { + /* + * \todo Try to find a better API that would make this error + * impossible. + */ + LOG(Camera, Error) + << "Buffers must be freed before the camera can be reconfigured"; + return -EBUSY; + } + pipe_->unlock(); state_ = CameraAvailable; @@ -649,6 +660,12 @@ int Camera::configure(CameraConfiguration *config) if (!stateBetween(CameraAcquired, CameraConfigured)) return -EACCES; + if (allocator_ && allocator_->allocated()) { + LOG(Camera, Error) + << "Allocator must be deleted before camera can be reconfigured"; + return -EBUSY; + } + if (config->validate() != CameraConfiguration::Valid) { LOG(Camera, Error) << "Can't configure camera with invalid configuration"; diff --git a/src/libcamera/framebuffer_allocator.cpp b/src/libcamera/framebuffer_allocator.cpp new file mode 100644 index 00000000..57789b24 --- /dev/null +++ b/src/libcamera/framebuffer_allocator.cpp @@ -0,0 +1,216 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * framebuffer_allocator.cpp - FrameBuffer allocator + */ + +#include + +#include + +#include +#include +#include + +#include "log.h" +#include "pipeline_handler.h" + +/** + * \file framebuffer_allocator.h + * \brief FrameBuffer allocator + */ + +namespace libcamera { + +LOG_DEFINE_CATEGORY(Allocator) + +/** + * \class FrameBufferAllocator + * \brief FrameBuffer allocator for applications + * + * The libcamera API is designed to consume buffers provided by applications as + * FrameBuffer instances. This makes libcamera a user of buffers exported by + * other devices (such as displays or video encoders), or allocated from an + * external allocator (such as ION on Android platforms). In some situations, + * applications do not have any mean to allocate or get hold of suitable + * buffers, for instance when no other device is involved, on Linux platforms + * that lack a centralized allocator. The FrameBufferAllocator class provides a + * buffer allocator that can be used in these situations. + * + * Applications create a framebuffer allocator for a Camera, and use it to + * allocate buffers for streams of a CameraConfiguration with allocate(). They + * control which streams to allocate buffers for, and can thus use external + * buffers for a subset of the streams if desired. + * + * Buffers are deleted for a stream with free(), and destroying the allocator + * automatically deletes all allocated buffers. Applications own the buffers + * allocated by the FrameBufferAllocator and are responsible for ensuring the + * buffers are not deleted while they are in use (part of a Request that has + * been queued and hasn't completed yet). + * + * Usage of the FrameBufferAllocator is optional, if all buffers for a camera + * are provided externally applications shall not use this class. + */ + +/** + * \brief Create a FrameBuffer allocator + * \param[in] camera The camera the allocator serves + * + * A single allocator may be created for a Camera instance. + * + * The caller is responsible for deleting the allocator before the camera is + * released. + * + * \return A pointer to the newly created allocator object or nullptr on error + */ +FrameBufferAllocator * +FrameBufferAllocator::create(std::shared_ptr camera) +{ + if (camera->allocator_) { + LOG(Allocator, Error) << "Camera already has an allocator"; + return nullptr; + } + + camera->allocator_ = new FrameBufferAllocator(camera); + return camera->allocator_; +} + +/** + * \brief Construct a FrameBufferAllocator serving a camera + * \param[in] camera The camera + */ +FrameBufferAllocator::FrameBufferAllocator(std::shared_ptr camera) + : camera_(camera) +{ +} + +FrameBufferAllocator::~FrameBufferAllocator() +{ + for (auto &value : buffers_) { + Stream *stream = value.first; + camera_->pipe_->freeFrameBuffers(camera_.get(), stream); + } + + buffers_.clear(); + + camera_->allocator_ = nullptr; +} + +/** + * \brief Allocate buffers for a configured stream + * \param[in] stream The stream to allocate buffers for + * + * Allocate buffers suitable for capturing frames from the \a stream. The Camera + * shall have been previously configured with Camera::configure() and shall be + * stopped, and the stream shall be part of the active camera configuration. + * + * Upon successful allocation, the allocated buffers can be retrieved with the + * buffers() method. + * + * \return 0 on success or a negative error code otherwise + * \retval -EACCES The camera is not in a state where buffers can be allocated + * \retval -EINVAL The \a stream does not belong to the camera or the stream is + * not part of the active camera configuration + * \retval -EBUSY Buffers are already allocated for the \a stream + */ +int FrameBufferAllocator::allocate(Stream *stream) +{ + if (camera_->state_ != Camera::CameraConfigured && + camera_->state_ != Camera::CameraPrepared) { + LOG(Allocator, Error) + << "Camera must be in the configured state to allocate buffers"; + return -EACCES; + } + + if (camera_->streams().find(stream) == camera_->streams().end()) { + LOG(Allocator, Error) + << "Stream does not belong to " << camera_->name(); + return -EINVAL; + } + + if (camera_->activeStreams_.find(stream) == camera_->activeStreams_.end()) { + LOG(Allocator, Error) + << "Stream is not part of " << camera_->name() + << " active configuration"; + return -EINVAL; + } + + if (buffers_.count(stream)) { + LOG(Allocator, Error) << "Buffers already allocated for stream"; + return -EBUSY; + } + + int ret = camera_->pipe_->exportFrameBuffers(camera_.get(), stream, + &buffers_[stream]); + if (ret) + return ret; + + return 0; +} + +/** + * \brief Free buffers previously allocated for a \a stream + * \param[in] stream The stream + * + * Free buffers allocated with allocate(). + * + * This invalidates the buffers returned by buffers(). + * + * \return 0 on success or a negative error code otherwise + * \retval -EACCES The camera is not in a state where buffers can be freed + * \retval -EINVAL The allocator do not handle the \a stream + */ +int FrameBufferAllocator::free(Stream *stream) +{ + if (camera_->state_ != Camera::CameraConfigured && camera_->state_ != Camera::CameraPrepared) { + LOG(Allocator, Error) + << "Camera must be in the configured state to free buffers"; + return -EACCES; + } + + auto iter = buffers_.find(stream); + if (iter == buffers_.end()) + return -EINVAL; + + std::vector> &buffers = iter->second; + + buffers.clear(); + + camera_->pipe_->freeFrameBuffers(camera_.get(), stream); + + buffers_.erase(iter); + + return 0; +} + +/** + * \fn FrameBufferAllocator::allocated() + * \brief Check if the allocator has allocated buffers for any stream + * \return True if the allocator has allocated buffers for one or more + * streams, false otherwise + */ + +/** + * \brief Retrieve the buffers allocated for a \a stream + * \param[in] stream The stream to retrive buffers for + * + * This method shall only be called after successfully allocating buffers for + * \a stream with allocate(). The returned buffers are valid until free() is + * called for the same stream or the FrameBufferAllocator instance is destroyed. + * + * \return The buffers allocated for the \a stream + */ +const std::vector> & +FrameBufferAllocator::buffers(Stream *stream) const +{ + static std::vector> empty; + + auto iter = buffers_.find(stream); + if (iter == buffers_.end()) + return empty; + + return iter->second; +} + +} /* namespace libcamera */ diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build index 722c5bc1..68d89559 100644 --- a/src/libcamera/meson.build +++ b/src/libcamera/meson.build @@ -16,6 +16,7 @@ libcamera_sources = files([ 'event_notifier.cpp', 'file_descriptor.cpp', 'formats.cpp', + 'framebuffer_allocator.cpp', 'geometry.cpp', 'ipa_context_wrapper.cpp', 'ipa_controls.cpp', -- cgit v1.2.1