[libcamera-devel] [PATCH 1/2] android: CameraBuffer: Add option of not mapping a buffer

[Hirokazu Honda]

CameraBuffer always maps a buffer in constructor. This adds an
option to not map a buffer within CameraBuffer. The option is
useful for a caller to only validate a buffer and not have to
map the buffer.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
---
 src/android/camera_buffer.h              |  7 ++++---
 src/android/mm/cros_camera_buffer.cpp    | 17 +++++++++++++----
 src/android/mm/generic_camera_buffer.cpp | 20 ++++++++++++--------
 3 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
index 7e8970b4..1fdb76a6 100644
--- a/src/android/camera_buffer.h
+++ b/src/android/camera_buffer.h
@@ -17,7 +17,7 @@ class CameraBuffer final : public libcamera::Extensible
 	LIBCAMERA_DECLARE_PRIVATE(CameraBuffer)
 
 public:
-	CameraBuffer(buffer_handle_t camera3Buffer, int flags);
+	CameraBuffer(buffer_handle_t camera3Buffer, int flags, bool map = true);
 	~CameraBuffer();
 
 	bool isValid() const;
@@ -31,8 +31,9 @@ public:
 };
 
 #define PUBLIC_CAMERA_BUFFER_IMPLEMENTATION				\
-CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)	\
-	: Extensible(new Private(this, camera3Buffer, flags))		\
+	CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags, \
+				   bool map)				\
+		: Extensible(new Private(this, camera3Buffer, flags, map))\
 {									\
 }									\
 CameraBuffer::~CameraBuffer()						\
diff --git a/src/android/mm/cros_camera_buffer.cpp b/src/android/mm/cros_camera_buffer.cpp
index 1a4fd5d1..71e03766 100644
--- a/src/android/mm/cros_camera_buffer.cpp
+++ b/src/android/mm/cros_camera_buffer.cpp
@@ -21,7 +21,7 @@ class CameraBuffer::Private : public Extensible::Private
 
 public:
 	Private(CameraBuffer *cameraBuffer,
-		buffer_handle_t camera3Buffer, int flags);
+		buffer_handle_t camera3Buffer, int flags, bool map);
 	~Private();
 
 	bool isValid() const { return valid_; }
@@ -38,6 +38,7 @@ private:
 	unsigned int numPlanes_;
 	bool valid_;
 	bool registered_;
+	bool map_;
 	union {
 		void *addr;
 		android_ycbcr ycbcr;
@@ -48,9 +49,10 @@ private:
 };
 
 CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
-			       buffer_handle_t camera3Buffer, int flags)
+			       buffer_handle_t camera3Buffer, int flags,
+			       bool map)
 	: Extensible::Private(cameraBuffer), handle_(camera3Buffer),
-	  numPlanes_(0), valid_(false), registered_(false)
+	  numPlanes_(0), valid_(false), registered_(false), map_(map)
 {
 	bufferManager_ = cros::CameraBufferManager::GetInstance();
 
@@ -62,6 +64,13 @@ CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
 
 	registered_ = true;
 	numPlanes_ = bufferManager_->GetNumPlanes(camera3Buffer);
+
+	memset(&mem, 0, sizeof(mem));
+	if (!map_) {
+		valid_ = true;
+		return;
+	}
+
 	switch (numPlanes_) {
 	case 1: {
 		ret = bufferManager_->Lock(handle_, 0, 0, 0, 0, 0, &mem.addr);
@@ -91,7 +100,7 @@ CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
 
 CameraBuffer::Private::~Private()
 {
-	if (valid_)
+	if (map_ && valid_)
 		bufferManager_->Unlock(handle_);
 	if (registered_)
 		bufferManager_->Deregister(handle_);
diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
index 929e078a..8fa79889 100644
--- a/src/android/mm/generic_camera_buffer.cpp
+++ b/src/android/mm/generic_camera_buffer.cpp
@@ -21,7 +21,7 @@ class CameraBuffer::Private : public Extensible::Private,
 
 public:
 	Private(CameraBuffer *cameraBuffer,
-		buffer_handle_t camera3Buffer, int flags);
+		buffer_handle_t camera3Buffer, int flags, bool map);
 	~Private();
 
 	unsigned int numPlanes() const;
@@ -32,7 +32,8 @@ public:
 };
 
 CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
-			       buffer_handle_t camera3Buffer, int flags)
+			       buffer_handle_t camera3Buffer,
+			       int flags, bool map)
 	: Extensible::Private(cameraBuffer)
 {
 	maps_.reserve(camera3Buffer->numFds);
@@ -49,12 +50,15 @@ CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
 			break;
 		}
 
-		void *address = mmap(nullptr, length, flags, MAP_SHARED,
-				     camera3Buffer->data[i], 0);
-		if (address == MAP_FAILED) {
-			error_ = -errno;
-			LOG(HAL, Error) << "Failed to mmap plane";
-			break;
+		void *address = nullptr;
+		if (map) {
+			mmap(nullptr, length, flags, MAP_SHARED,
+			     camera3Buffer->data[i], 0);
+			if (address == MAP_FAILED) {
+				error_ = -errno;
+				LOG(HAL, Error) << "Failed to mmap plane";
+				break;
+			}
 		}
 
 		maps_.emplace_back(static_cast<uint8_t *>(address),
-- 
2.31.0.208.g409f899ff0-goog