libcamera: buffer: Switch from Plane to FrameBuffer::Plane

It is not libcamera's responsibility to handle memory mappings. Switch
from the soon to be removed Plane class which deals with memory
mappings to FrameBuffer::Plane which just describes it. This makes the
transition to the full FrameBuffer easier.

As the full FrameBuffer interface has not yet spread to all parts of
libcamera core it is hard to create efficient caching of memory mappings
in the qcam application. This will be fixed in a later patch, for now
the dmabuf is mapped and unmapped each time it is seen by the
application.

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

7 files changed, 34 insertions, 28 deletions

diff --git a/src/cam/buffer_writer.cpp b/src/cam/buffer_writer.cpp
index c33e99c5..765a1762 100644
--- a/src/cam/buffer_writer.cpp
+++ b/src/cam/buffer_writer.cpp
@@ -10,6 +10,7 @@
 #include <iostream>
 #include <sstream>
 #include <string.h>
+#include <sys/mman.h>
 #include <unistd.h>
 
 #include "buffer_writer.h"
@@ -43,9 +44,11 @@ int BufferWriter::write(Buffer *buffer, const std::string &streamName)
 		return -errno;
 
 	BufferMemory *mem = buffer->mem();
-	for (Plane &plane : mem->planes()) {
-		void *data = plane.mem();
-		unsigned int length = plane.length();
+	for (const FrameBuffer::Plane &plane : mem->planes()) {
+		/* \todo Once the FrameBuffer is done cache mapped memory. */
+		void *data = mmap(NULL, plane.length, PROT_READ, MAP_SHARED,
+				  plane.fd.fd(), 0);
+		unsigned int length = plane.length;
 
 		ret = ::write(fd, data, length);
 		if (ret < 0) {
@@ -59,6 +62,8 @@ int BufferWriter::write(Buffer *buffer, const std::string &streamName)
 				  << length << std::endl;
 			break;
 		}
+
+		munmap(data, length);
 	}
 
 	close(fd);
diff --git a/src/libcamera/buffer.cpp b/src/libcamera/buffer.cpp
index 2178bd2f..ec7c614d 100644
--- a/src/libcamera/buffer.cpp
+++ b/src/libcamera/buffer.cpp
@@ -257,13 +257,13 @@ void *Plane::mem()
 /**
  * \fn BufferMemory::planes() const
  * \brief Retrieve the planes within the buffer
- * \return A const reference to a vector holding all Planes within the buffer
+ * \return A const reference to a vector holding all planes within the buffer
  */
 
 /**
  * \fn BufferMemory::planes()
  * \brief Retrieve the planes within the buffer
- * \return A reference to a vector holding all Planes within the buffer
+ * \return A reference to a vector holding all planes within the buffer
  */
 
 /**
diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
index d7ee95de..1e445715 100644
--- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
+++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
@@ -687,22 +687,14 @@ int PipelineHandlerRkISP1::allocateBuffers(Camera *camera,
 	}
 
 	for (unsigned int i = 0; i < stream->configuration().bufferCount + 1; i++) {
-		FrameBuffer::Plane plane;
-		plane.fd = FileDescriptor(paramPool_.buffers()[i].planes()[0].dmabuf());
-		plane.length = paramPool_.buffers()[i].planes()[0].length();
-
 		data->ipaBuffers_.push_back({ .id = RKISP1_PARAM_BASE | i,
-					      .planes = { plane } });
+					      .planes = paramPool_.buffers()[i].planes() });
 		paramBuffers_.push(new Buffer(i));
 	}
 
 	for (unsigned int i = 0; i < stream->configuration().bufferCount + 1; i++) {
-		FrameBuffer::Plane plane;
-		plane.fd = FileDescriptor(statPool_.buffers()[i].planes()[0].dmabuf());
-		plane.length = statPool_.buffers()[i].planes()[0].length();
-
 		data->ipaBuffers_.push_back({ .id = RKISP1_STAT_BASE | i,
-					      .planes = { plane } });
+					      .planes = statPool_.buffers()[i].planes() });
 		statBuffers_.push(new Buffer(i));
 	}
 
diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
index 45f31ae1..16a323f1 100644
--- a/src/libcamera/stream.cpp
+++ b/src/libcamera/stream.cpp
@@ -577,8 +577,10 @@ int Stream::mapBuffer(const Buffer *buffer)
 		if (dmabufs[i] == -1)
 			break;
 
-		mem->planes().emplace_back();
-		mem->planes().back().setDmabuf(dmabufs[i], 0);
+		FrameBuffer::Plane plane;
+		plane.fd = FileDescriptor(dmabufs[i]);
+		plane.length = 0;
+		mem->planes().push_back(plane);
 	}
 
 	/* Remove the buffer from the cache and return its index. */
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 033f7cc0..1dc9e193 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -922,9 +922,10 @@ int V4L2VideoDevice::createPlane(BufferMemory *buffer, unsigned int index,
 		return ret;
 	}
 
-	buffer->planes().emplace_back();
-	Plane &plane = buffer->planes().back();
-	plane.setDmabuf(expbuf.fd, length);
+	FrameBuffer::Plane plane;
+	plane.fd = FileDescriptor(expbuf.fd);
+	plane.length = length;
+	buffer->planes().push_back(plane);
 	::close(expbuf.fd);
 
 	return 0;
@@ -987,14 +988,14 @@ int V4L2VideoDevice::queueBuffer(Buffer *buffer)
 
 	bool multiPlanar = V4L2_TYPE_IS_MULTIPLANAR(buf.type);
 	BufferMemory *mem = &bufferPool_->buffers()[buf.index];
-	const std::vector<Plane> &planes = mem->planes();
+	const std::vector<FrameBuffer::Plane> &planes = mem->planes();
 
 	if (buf.memory == V4L2_MEMORY_DMABUF) {
 		if (multiPlanar) {
 			for (unsigned int p = 0; p < planes.size(); ++p)
-				v4l2Planes[p].m.fd = planes[p].dmabuf();
+				v4l2Planes[p].m.fd = planes[p].fd.fd();
 		} else {
-			buf.m.fd = planes[0].dmabuf();
+			buf.m.fd = planes[0].fd.fd();
 		}
 	}
 
diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index 0c7ca61a..0a353e8b 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -8,6 +8,7 @@
 #include <iomanip>
 #include <iostream>
 #include <string>
+#include <sys/mman.h>
 
 #include <QCoreApplication>
 #include <QInputDialog>
@@ -296,13 +297,18 @@ void MainWindow::requestComplete(Request *request)
 
 int MainWindow::display(Buffer *buffer)
 {
-	BufferMemory *mem = buffer->mem();
-	if (mem->planes().size() != 1)
+	if (buffer->mem()->planes().size() != 1)
 		return -EINVAL;
 
-	Plane &plane = mem->planes().front();
-	unsigned char *raw = static_cast<unsigned char *>(plane.mem());
+	/* \todo Once the FrameBuffer is done cache mapped memory. */
+	const FrameBuffer::Plane &plane = buffer->mem()->planes().front();
+	void *memory = mmap(NULL, plane.length, PROT_READ, MAP_SHARED,
+			    plane.fd.fd(), 0);
+
+	unsigned char *raw = static_cast<unsigned char *>(memory);
 	viewfinder_->display(raw, buffer->bytesused());
 
+	munmap(memory, plane.length);
+
 	return 0;
 }
diff --git a/src/v4l2/v4l2_camera.cpp b/src/v4l2/v4l2_camera.cpp
index 07f05a31..7221755d 100644
--- a/src/v4l2/v4l2_camera.cpp
+++ b/src/v4l2/v4l2_camera.cpp
@@ -135,7 +135,7 @@ void V4L2Camera::freeBuffers()
 FileDescriptor V4L2Camera::getBufferFd(unsigned int index)
 {
 	Stream *stream = *camera_->streams().begin();
-	return FileDescriptor(stream->buffers()[index].planes()[0].dmabuf());
+	return stream->buffers()[index].planes()[0].fd;
 }
 
 int V4L2Camera::streamOn()