android: camera_stream: Create buffer pool

Add a FrameBufferAllocator class member to the CameraStream class.
The allocator is constructed for CameraStream instances that needs
internal allocation and automatically deleted.

Allocate FrameBuffers using the allocator_ class member in the
CameraStream class at CameraStream::configure() time and add two
methods to the CameraStream class to get and put FrameBuffer pointers
from the pool of allocated buffers. As buffer allocation can take place
only after the Camera has been configured, move the CameraStream
configuration loop in the CameraDevice class after camera_->configure()
call.

The newly created pool will be used to provide buffers to CameraStream
that need to provide memory to libcamera where to deliver frames.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
index f899be4f..eac14805 100644
--- a/src/android/camera_stream.cpp
+++ b/src/android/camera_stream.cpp
@@ -26,6 +26,11 @@ CameraStream::CameraStream(CameraDevice *cameraDevice, Type type,
 
 	if (type_ == Type::Internal || type_ == Type::Mapped)
 		encoder_ = std::make_unique<EncoderLibJpeg>();
+
+	if (type == Type::Internal) {
+		allocator_ = std::make_unique<FrameBufferAllocator>(cameraDevice_->camera());
+		mutex_ = std::make_unique<std::mutex>();
+	}
 }
 
 const StreamConfiguration &CameraStream::configuration() const
@@ -46,6 +51,16 @@ int CameraStream::configure()
 			return ret;
 	}
 
+	if (allocator_) {
+		int ret = allocator_->allocate(stream());
+		if (ret < 0)
+			return ret;
+
+		/* Save a pointer to the reserved frame buffers */
+		for (const auto &frameBuffer : allocator_->buffers(stream()))
+			buffers_.push_back(frameBuffer.get());
+	}
+
 	camera3Stream_->max_buffers = configuration().bufferCount;
 
 	return 0;
@@ -109,3 +124,31 @@ int CameraStream::process(const libcamera::FrameBuffer &source,
 
 	return 0;
 }
+
+FrameBuffer *CameraStream::getBuffer()
+{
+	if (!allocator_)
+		return nullptr;
+
+	std::lock_guard<std::mutex> locker(*mutex_);
+
+	if (buffers_.empty()) {
+		LOG(HAL, Error) << "Buffer underrun";
+		return nullptr;
+	}
+
+	FrameBuffer *buffer = buffers_.back();
+	buffers_.pop_back();
+
+	return buffer;
+}
+
+void CameraStream::putBuffer(libcamera::FrameBuffer *buffer)
+{
+	if (!allocator_)
+		return;
+
+	std::lock_guard<std::mutex> locker(*mutex_);
+
+	buffers_.push_back(buffer);
+}