[libcamera-devel] [PATCH v3 1/2] pipeline: raspberrypi: Use MappedFrameBuffer for embedded data buffers

[Naushir Patuck]

Use a MappedFrameBuffer to mmap embedded data buffers for the pipeline
handler to use in the cases where the sensor does not fill it in. This
avoids the need to mmap and unmap on every frame.

Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 .../pipeline/raspberrypi/raspberrypi.cpp      | 33 ++++++++++++++-----
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index dd62dfc7..9fe5eb05 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -24,6 +24,7 @@
 #include <linux/videodev2.h>
 
 #include "libcamera/internal/bayer_format.h"
+#include "libcamera/internal/buffer.h"
 #include "libcamera/internal/camera_sensor.h"
 #include "libcamera/internal/device_enumerator.h"
 #include "libcamera/internal/ipa_manager.h"
@@ -165,6 +166,12 @@ public:
 	/* Stores the ids of the buffers mapped in the IPA. */
 	std::unordered_set<unsigned int> ipaBuffers_;
 
+	/*
+	 * Map of (internal) mmaped embedded data buffers, to avoid having to
+	 * map/unmap on every frame.
+	 */
+	std::map<unsigned int, MappedFrameBuffer> mappedEmbeddedBuffers_;
+
 	/* DMAHEAP allocation helper. */
 	RPi::DmaHeap dmaHeap_;
 	FileDescriptor lsTable_;
@@ -1040,6 +1047,13 @@ int PipelineHandlerRPi::prepareBuffers(Camera *camera)
 			return ret;
 	}
 
+	if (!data->sensorMetadata_) {
+		for (auto const &it : data->unicam_[Unicam::Embedded].getBuffers()) {
+			MappedFrameBuffer fb(it.second, PROT_READ | PROT_WRITE);
+			data->mappedEmbeddedBuffers_.emplace(it.first, std::move(fb));
+		}
+	}
+
 	/*
 	 * Pass the stats and embedded data buffers to the IPA. No other
 	 * buffers need to be passed.
@@ -1078,6 +1092,7 @@ void PipelineHandlerRPi::freeBuffers(Camera *camera)
 	std::vector<unsigned int> ipaBuffers(data->ipaBuffers_.begin(), data->ipaBuffers_.end());
 	data->ipa_->unmapBuffers(ipaBuffers);
 	data->ipaBuffers_.clear();
+	data->mappedEmbeddedBuffers_.clear();
 
 	for (auto const stream : data->streams_)
 		stream->releaseBuffers();
@@ -1310,14 +1325,16 @@ void RPiCameraData::unicamBufferDequeue(FrameBuffer *buffer)
 		 * metadata buffer.
 		 */
 		if (!sensorMetadata_) {
-			const FrameBuffer &fb = buffer->planes();
-			uint32_t *mem = static_cast<uint32_t *>(::mmap(nullptr, fb.planes()[0].length,
-								       PROT_READ | PROT_WRITE,
-								       MAP_SHARED,
-								       fb.planes()[0].fd.fd(), 0));
-			mem[0] = ctrl[V4L2_CID_EXPOSURE];
-			mem[1] = ctrl[V4L2_CID_ANALOGUE_GAIN];
-			munmap(mem, fb.planes()[0].length);
+			unsigned int bufferId = unicam_[Unicam::Embedded].getBufferId(buffer);
+			auto it = mappedEmbeddedBuffers_.find(bufferId);
+			if (it != mappedEmbeddedBuffers_.end()) {
+				uint32_t *mem = reinterpret_cast<uint32_t *>(it->second.maps()[0].data());
+				mem[0] = ctrl[V4L2_CID_EXPOSURE];
+				mem[1] = ctrl[V4L2_CID_ANALOGUE_GAIN];
+			} else {
+				LOG(RPI, Warning) << "Failed to find embedded buffer "
+						  << bufferId;
+			}
 		}
 	}
 
-- 
2.25.1