[libcamera-devel] [PATCH] libcamera: MappedFrameBuffer: Use typed Flags<MapModes>

Kieran Bingham kieran.bingham at ideasonboard.com
Fri Aug 6 15:15:11 CEST 2021


Remove the need for callers to reference PROT_READ/PROT_WRITE directly
from <sys/mman.h> by instead exposing the Read/Write mapping options as
flags from the MappedFrameBuffer class itself.

While here, introduce the <stdint.h> header which is required for the
int8_t as part of the Plane.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 .../libcamera/internal/mapped_framebuffer.h   | 14 ++++++++--
 src/android/jpeg/encoder_libjpeg.cpp          |  2 +-
 src/android/jpeg/thumbnailer.cpp              |  2 +-
 src/android/yuv/post_processor_yuv.cpp        |  2 +-
 src/ipa/ipu3/ipu3.cpp                         |  2 +-
 src/ipa/raspberrypi/raspberrypi.cpp           |  2 +-
 src/libcamera/mapped_framebuffer.cpp          | 28 +++++++++++++++++--
 test/mapped-buffer.cpp                        |  6 ++--
 8 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/include/libcamera/internal/mapped_framebuffer.h b/include/libcamera/internal/mapped_framebuffer.h
index 41e587364260..24bd2c50cd27 100644
--- a/include/libcamera/internal/mapped_framebuffer.h
+++ b/include/libcamera/internal/mapped_framebuffer.h
@@ -7,10 +7,11 @@
 #ifndef __LIBCAMERA_INTERNAL_MAPPED_FRAMEBUFFER_H__
 #define __LIBCAMERA_INTERNAL_MAPPED_FRAMEBUFFER_H__
 
-#include <sys/mman.h>
+#include <stdint.h>
 #include <vector>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/flags.h>
 #include <libcamera/base/span.h>
 
 #include <libcamera/framebuffer.h>
@@ -44,7 +45,16 @@ private:
 class MappedFrameBuffer : public MappedBuffer
 {
 public:
-	MappedFrameBuffer(const FrameBuffer *buffer, int flags);
+	enum MapModes {
+		Read = 0 << 1,
+		Write = 1 << 1,
+
+		ReadWrite = Read | Write,
+	};
+
+	using MapMode = Flags<MapModes>;
+
+	MappedFrameBuffer(const FrameBuffer *buffer, MapMode flags);
 };
 
 } /* namespace libcamera */
diff --git a/src/android/jpeg/encoder_libjpeg.cpp b/src/android/jpeg/encoder_libjpeg.cpp
index 372018d2207f..c37611f6b6cd 100644
--- a/src/android/jpeg/encoder_libjpeg.cpp
+++ b/src/android/jpeg/encoder_libjpeg.cpp
@@ -182,7 +182,7 @@ void EncoderLibJpeg::compressNV(Span<const uint8_t> frame)
 int EncoderLibJpeg::encode(const FrameBuffer &source, Span<uint8_t> dest,
 			   Span<const uint8_t> exifData, unsigned int quality)
 {
-	MappedFrameBuffer frame(&source, PROT_READ);
+	MappedFrameBuffer frame(&source, MappedFrameBuffer::Read);
 	if (!frame.isValid()) {
 		LOG(JPEG, Error) << "Failed to map FrameBuffer : "
 				 << strerror(frame.error());
diff --git a/src/android/jpeg/thumbnailer.cpp b/src/android/jpeg/thumbnailer.cpp
index 535e2cece914..17196b2dd257 100644
--- a/src/android/jpeg/thumbnailer.cpp
+++ b/src/android/jpeg/thumbnailer.cpp
@@ -41,7 +41,7 @@ void Thumbnailer::createThumbnail(const FrameBuffer &source,
 				  const Size &targetSize,
 				  std::vector<unsigned char> *destination)
 {
-	MappedFrameBuffer frame(&source, PROT_READ);
+	MappedFrameBuffer frame(&source, MappedFrameBuffer::Read);
 	if (!frame.isValid()) {
 		LOG(Thumbnailer, Error)
 			<< "Failed to map FrameBuffer : "
diff --git a/src/android/yuv/post_processor_yuv.cpp b/src/android/yuv/post_processor_yuv.cpp
index 509d4244d614..6f599a82a3a0 100644
--- a/src/android/yuv/post_processor_yuv.cpp
+++ b/src/android/yuv/post_processor_yuv.cpp
@@ -57,7 +57,7 @@ int PostProcessorYuv::process(const FrameBuffer &source,
 	if (!isValidBuffers(source, *destination))
 		return -EINVAL;
 
-	const MappedFrameBuffer sourceMapped(&source, PROT_READ);
+	const MappedFrameBuffer sourceMapped(&source, MappedFrameBuffer::Read);
 	if (!sourceMapped.isValid()) {
 		LOG(YUV, Error) << "Failed to mmap camera frame buffer";
 		return -EINVAL;
diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
index 2647bf2f3b96..6028638c314c 100644
--- a/src/ipa/ipu3/ipu3.cpp
+++ b/src/ipa/ipu3/ipu3.cpp
@@ -211,7 +211,7 @@ void IPAIPU3::mapBuffers(const std::vector<IPABuffer> &buffers)
 	for (const IPABuffer &buffer : buffers) {
 		const FrameBuffer fb(buffer.planes);
 		buffers_.emplace(buffer.id,
-				 MappedFrameBuffer(&fb, PROT_READ | PROT_WRITE));
+				 MappedFrameBuffer(&fb, MappedFrameBuffer::ReadWrite));
 	}
 }
 
diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 76f67dd4567a..b905a9ca1dbf 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -411,7 +411,7 @@ void IPARPi::mapBuffers(const std::vector<IPABuffer> &buffers)
 {
 	for (const IPABuffer &buffer : buffers) {
 		const FrameBuffer fb(buffer.planes);
-		buffers_.emplace(buffer.id, MappedFrameBuffer(&fb, PROT_READ | PROT_WRITE));
+		buffers_.emplace(buffer.id, MappedFrameBuffer(&fb, MappedFrameBuffer::ReadWrite));
 	}
 }
 
diff --git a/src/libcamera/mapped_framebuffer.cpp b/src/libcamera/mapped_framebuffer.cpp
index 0e30fc542154..65bdf9249133 100644
--- a/src/libcamera/mapped_framebuffer.cpp
+++ b/src/libcamera/mapped_framebuffer.cpp
@@ -142,6 +142,22 @@ MappedBuffer::~MappedBuffer()
  * \brief Map a FrameBuffer using the MappedBuffer interface
  */
 
+/**
+ * \enum MappedFrameBuffer::MapModes
+ * \brief Specify the mapping mode for the FrameBuffer
+ * \var MappedFrameBuffer::Read
+ * \brief Create a Read-only mapping
+ * \var MappedFrameBuffer::Write
+ * \brief Create a Write-only mapping
+ * \var MappedFrameBuffer::ReadWrite
+ * \brief Create a mapping with both read and write capabilities
+ */
+
+/**
+ * \typedef MappedFrameBuffer::MapMode
+ * \brief A bitwise combination of MappedFrameBuffer::MapModes values
+ */
+
 /**
  * \brief Map all planes of a FrameBuffer
  * \param[in] buffer FrameBuffer to be mapped
@@ -151,12 +167,20 @@ MappedBuffer::~MappedBuffer()
  * The flags are passed directly to mmap and should be either PROT_READ,
  * PROT_WRITE, or a bitwise-or combination of both.
  */
-MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, int flags)
+MappedFrameBuffer::MappedFrameBuffer(const FrameBuffer *buffer, MapMode flags)
 {
 	maps_.reserve(buffer->planes().size());
 
+	int mmap_flags = 0;
+
+	if (flags & Read)
+		mmap_flags |= PROT_READ;
+
+	if (flags & Write)
+		mmap_flags |= PROT_WRITE;
+
 	for (const FrameBuffer::Plane &plane : buffer->planes()) {
-		void *address = mmap(nullptr, plane.length, flags,
+		void *address = mmap(nullptr, plane.length, mmap_flags,
 				     MAP_SHARED, plane.fd.fd(), 0);
 		if (address == MAP_FAILED) {
 			error_ = -errno;
diff --git a/test/mapped-buffer.cpp b/test/mapped-buffer.cpp
index a3d1511b74ce..ce75d9a9dbbd 100644
--- a/test/mapped-buffer.cpp
+++ b/test/mapped-buffer.cpp
@@ -71,7 +71,7 @@ protected:
 		const std::unique_ptr<FrameBuffer> &buffer = allocator_->buffers(stream_).front();
 		std::vector<MappedBuffer> maps;
 
-		MappedFrameBuffer map(buffer.get(), PROT_READ);
+		MappedFrameBuffer map(buffer.get(), MappedFrameBuffer::Read);
 		if (!map.isValid()) {
 			cout << "Failed to successfully map buffer" << endl;
 			return TestFail;
@@ -90,13 +90,13 @@ protected:
 		}
 
 		/* Test for multiple successful maps on the same buffer. */
-		MappedFrameBuffer write_map(buffer.get(), PROT_WRITE);
+		MappedFrameBuffer write_map(buffer.get(), MappedFrameBuffer::Write);
 		if (!write_map.isValid()) {
 			cout << "Failed to map write buffer" << endl;
 			return TestFail;
 		}
 
-		MappedFrameBuffer rw_map(buffer.get(), PROT_READ | PROT_WRITE);
+		MappedFrameBuffer rw_map(buffer.get(), MappedFrameBuffer::ReadWrite);
 		if (!rw_map.isValid()) {
 			cout << "Failed to map RW buffer" << endl;
 			return TestFail;
-- 
2.30.2



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