[libcamera-devel] [PATCH 2/9] libcamera: stream: Add Stream memory type

[Jacopo Mondi]

Define the memory type a Stream uses and allow application to set it
through the associated StreamConfiguration.

A Stream can use either internal or external memory allocation methods,
depending on where the data produced by the stream is actually saved.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 include/libcamera/stream.h |  8 ++++++++
 src/libcamera/camera.cpp   |  1 +
 src/libcamera/stream.cpp   | 30 ++++++++++++++++++++++++++++--
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
index fa7d6ba4987c..796f1aff2602 100644
--- a/include/libcamera/stream.h
+++ b/include/libcamera/stream.h
@@ -34,6 +34,11 @@ private:
 	std::map<unsigned int, std::vector<SizeRange>> formats_;
 };
 
+enum MemoryType {
+	InternalMemory,
+	ExternalMemory,
+};
+
 struct StreamConfiguration {
 	StreamConfiguration();
 	StreamConfiguration(const StreamFormats &formats);
@@ -41,6 +46,7 @@ struct StreamConfiguration {
 	unsigned int pixelFormat;
 	Size size;
 
+	MemoryType memoryType;
 	unsigned int bufferCount;
 
 	Stream *stream() const { return stream_; }
@@ -77,6 +83,7 @@ public:
 	std::vector<Buffer> &buffers() { return bufferPool_.buffers(); }
 	unsigned int bufferCount() const { return bufferPool_.count(); }
 	const StreamConfiguration &configuration() const { return configuration_; }
+	MemoryType memoryType() const { return memoryType_; }
 
 protected:
 	friend class Camera;
@@ -86,6 +93,7 @@ protected:
 
 	BufferPool bufferPool_;
 	StreamConfiguration configuration_;
+	MemoryType memoryType_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 088a39623e36..5f756d41744a 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -683,6 +683,7 @@ int Camera::configure(CameraConfiguration *config)
 		 * Allocate buffer objects in the pool.
 		 * Memory will be allocated and assigned later.
 		 */
+		stream->memoryType_ = cfg.memoryType;
 		stream->createBuffers(cfg.bufferCount);
 	}
 
diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
index 35197be09c26..97e0f429c9fb 100644
--- a/src/libcamera/stream.cpp
+++ b/src/libcamera/stream.cpp
@@ -263,6 +263,16 @@ SizeRange StreamFormats::range(unsigned int pixelformat) const
 	return range;
 }
 
+/**
+ * \enum MemoryType
+ * \brief Define the memory type used by a Stream
+ * \var MemoryType::InternalMemory
+ * The Stream uses memory allocated internally to the library and export that
+ * to applications.
+ * \var MemoryType::ExternalMemory
+ * The Stream uses buffers whose memory is allocated outside from the library.
+ */
+
 /**
  * \struct StreamConfiguration
  * \brief Configuration parameters for a stream
@@ -276,7 +286,7 @@ SizeRange StreamFormats::range(unsigned int pixelformat) const
  * handlers provied StreamFormats.
  */
 StreamConfiguration::StreamConfiguration()
-	: stream_(nullptr)
+	: memoryType(InternalMemory), stream_(nullptr)
 {
 }
 
@@ -284,7 +294,7 @@ StreamConfiguration::StreamConfiguration()
  * \brief Construct a configuration with stream formats
  */
 StreamConfiguration::StreamConfiguration(const StreamFormats &formats)
-	: stream_(nullptr), formats_(formats)
+	: memoryType(InternalMemory), stream_(nullptr), formats_(formats)
 {
 }
 
@@ -301,6 +311,11 @@ StreamConfiguration::StreamConfiguration(const StreamFormats &formats)
  * format described in V4L2 using the V4L2_PIX_FMT_* definitions.
  */
 
+/**
+ * \var StreamConfiguration::memoryType
+ * \brief The memory type the stream shall use
+ */
+
 /**
  * \var StreamConfiguration::bufferCount
  * \brief Requested number of buffers to allocate for the stream
@@ -436,6 +451,12 @@ Stream::Stream()
  * \return The active configuration of the stream
  */
 
+/**
+ * \fn Stream::memoryType()
+ * \brief Retrieve the stream memory type
+ * \return The memory type used by the stream
+ */
+
 /**
  * \brief Create buffers for the stream
  * \param count The number of buffers to create
@@ -476,4 +497,9 @@ void Stream::destroyBuffers()
  * next call to Camera::configure() regardless of if it includes the stream.
  */
 
+/**
+ * \var Stream::memoryType_
+ * \brief The stream memory type
+ */
+
 } /* namespace libcamera */
-- 
2.21.0