libcamera: Add Buffer Management

Provide classes that represent frame buffers and pools of frame buffers.

An image within the system may use one or more Plane objects to track each
plane in the case of multi-planar image formats. The Buffer class manages all
of the data required to render or interpret the raw image data.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

3 files changed, 76 insertions, 0 deletions

diff --git a/include/libcamera/buffer.h b/include/libcamera/buffer.h
new file mode 100644
index 00000000..21a1ec4c
--- /dev/null
+++ b/include/libcamera/buffer.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * buffer.h - Buffer handling
+ */
+#ifndef __LIBCAMERA_BUFFER_H__
+#define __LIBCAMERA_BUFFER_H__
+
+#include <vector>
+
+#include <libcamera/signal.h>
+
+namespace libcamera {
+
+class BufferPool;
+
+class Plane final
+{
+public:
+	Plane();
+	~Plane();
+
+	int dmabuf() const { return fd_; }
+	int setDmabuf(int fd, unsigned int length);
+
+	void *mem();
+	unsigned int length() const { return length_; }
+
+private:
+	int mmap();
+	int munmap();
+
+	int fd_;
+	unsigned int length_;
+	void *mem_;
+};
+
+class Buffer final
+{
+public:
+	Buffer();
+
+	unsigned int index() const { return index_; }
+	std::vector<Plane> &planes() { return planes_; }
+
+	Signal<Buffer *> completed;
+
+private:
+	friend class BufferPool;
+
+	unsigned int index_;
+
+	std::vector<Plane> planes_;
+};
+
+class BufferPool final
+{
+public:
+	~BufferPool();
+
+	void createBuffers(unsigned int count);
+	void destroyBuffers();
+
+	unsigned int count() const { return buffers_.size(); }
+	std::vector<Buffer> &buffers() { return buffers_; }
+
+private:
+	std::vector<Buffer> buffers_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_BUFFER_H__ */
diff --git a/include/libcamera/libcamera.h b/include/libcamera/libcamera.h
index 272dfd5e..8167e809 100644
--- a/include/libcamera/libcamera.h
+++ b/include/libcamera/libcamera.h
@@ -7,6 +7,7 @@
 #ifndef __LIBCAMERA_LIBCAMERA_H__
 #define __LIBCAMERA_LIBCAMERA_H__
 
+#include <libcamera/buffer.h>
 #include <libcamera/camera.h>
 #include <libcamera/camera_manager.h>
 #include <libcamera/event_dispatcher.h>
diff --git a/include/libcamera/meson.build b/include/libcamera/meson.build
index 54a68078..8c14423b 100644
--- a/include/libcamera/meson.build
+++ b/include/libcamera/meson.build
@@ -1,4 +1,5 @@
 libcamera_api = files([
+    'buffer.h',
     'camera.h',
     'camera_manager.h',
     'event_dispatcher.h',