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Diffstat (limited to 'src/libcamera/framebuffer_allocator.cpp')
| -rw-r--r-- | src/libcamera/framebuffer_allocator.cpp | 216 |
1 files changed, 216 insertions, 0 deletions
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 <libcamera/framebuffer_allocator.h> + +#include <errno.h> + +#include <libcamera/buffer.h> +#include <libcamera/camera.h> +#include <libcamera/stream.h> + +#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> 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_(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<std::unique_ptr<FrameBuffer>> &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<std::unique_ptr<FrameBuffer>> & +FrameBufferAllocator::buffers(Stream *stream) const +{ + static std::vector<std::unique_ptr<FrameBuffer>> empty; + + auto iter = buffers_.find(stream); + if (iter == buffers_.end()) + return empty; + + return iter->second; +} + +} /* namespace libcamera */ |