libcamera: pipeline_handler: Keep track of MediaDevice

Instead of requiring each pipeline handle implementation to keep track
of calling release() on its media devices upon deletion, keep track of
them in the base class. Add a helper that pipeline handlers shall use
to acquire a media device instead of directly interacting with the
DeviceEnumerator.

This also means that pipeline handler implementations do no need to keep
a shared_ptr<> reference to the media devices they store locally as the
PipelineHandler base class will keep a shared_ptr<> reference to all
media devices consumed for the entire lifetime of the pipeline handler
implementation.

Centrally keeping track of media devices will also be beneficial
to implement exclusive access to pipelines across processes.

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

src/libcamera/include/pipeline_handler.h

@@ -22,6 +22,7 @@ class Camera;
 class CameraConfiguration;
 class CameraManager;
 class DeviceEnumerator;
+class DeviceMatch;
 class MediaDevice;
 class PipelineHandler;
 class Request;
@@ -53,6 +54,8 @@ public:
 	virtual ~PipelineHandler();
 
 	virtual bool match(DeviceEnumerator *enumerator) = 0;
+	MediaDevice *acquireMediaDevice(DeviceEnumerator *enumerator,
+					const DeviceMatch &dm);
 
 	virtual CameraConfiguration
 	streamConfiguration(Camera *camera, const std::vector<StreamUsage> &usages) = 0;
@@ -84,6 +87,7 @@ private:
 	void mediaDeviceDisconnected(MediaDevice *media);
 	virtual void disconnect();
 
+	std::vector<std::shared_ptr<MediaDevice>> mediaDevices_;
 	std::vector<std::weak_ptr<Camera>> cameras_;
 	std::map<const Camera *, std::unique_ptr<CameraData>> cameraData_;
 };

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -149,7 +149,6 @@ class PipelineHandlerIPU3 : public PipelineHandler
 {
 public:
 	PipelineHandlerIPU3(CameraManager *manager);
-	~PipelineHandlerIPU3();
 
 	CameraConfiguration
 	streamConfiguration(Camera *camera,
@@ -201,8 +200,8 @@ private:
 
 	ImgUDevice imgu0_;
 	ImgUDevice imgu1_;
-	std::shared_ptr<MediaDevice> cio2MediaDev_;
-	std::shared_ptr<MediaDevice> imguMediaDev_;
+	MediaDevice *cio2MediaDev_;
+	MediaDevice *imguMediaDev_;
 };
 
 PipelineHandlerIPU3::PipelineHandlerIPU3(CameraManager *manager)
@@ -210,15 +209,6 @@ PipelineHandlerIPU3::PipelineHandlerIPU3(CameraManager *manager)
 {
 }
 
-PipelineHandlerIPU3::~PipelineHandlerIPU3()
-{
-	if (cio2MediaDev_)
-		cio2MediaDev_->release();
-
-	if (imguMediaDev_)
-		imguMediaDev_->release();
-}
-
 CameraConfiguration
 PipelineHandlerIPU3::streamConfiguration(Camera *camera,
 					 const std::vector<StreamUsage> &usages)
@@ -614,20 +604,14 @@ bool PipelineHandlerIPU3::match(DeviceEnumerator *enumerator)
 	imgu_dm.add("ipu3-imgu 1 viewfinder");
 	imgu_dm.add("ipu3-imgu 1 3a stat");
 
-	cio2MediaDev_ = enumerator->search(cio2_dm);
+	cio2MediaDev_ = acquireMediaDevice(enumerator, cio2_dm);
 	if (!cio2MediaDev_)
 		return false;
 
-	if (!cio2MediaDev_->acquire())
-		return false;
-
-	imguMediaDev_ = enumerator->search(imgu_dm);
+	imguMediaDev_ = acquireMediaDevice(enumerator, imgu_dm);
 	if (!imguMediaDev_)
 		return false;
 
-	if (!imguMediaDev_->acquire())
-		return false;
-
 	/*
 	 * Disable all links that are enabled by default on CIO2, as camera
 	 * creation enables all valid links it finds.
@@ -682,11 +666,11 @@ int PipelineHandlerIPU3::registerCameras()
 {
 	int ret;
 
-	ret = imgu0_.init(imguMediaDev_.get(), 0);
+	ret = imgu0_.init(imguMediaDev_, 0);
 	if (ret)
 		return ret;
 
-	ret = imgu1_.init(imguMediaDev_.get(), 1);
+	ret = imgu1_.init(imguMediaDev_, 1);
 	if (ret)
 		return ret;
 
@@ -705,7 +689,7 @@ int PipelineHandlerIPU3::registerCameras()
 		};
 		CIO2Device *cio2 = &data->cio2_;
 
-		ret = cio2->init(cio2MediaDev_.get(), id);
+		ret = cio2->init(cio2MediaDev_, id);
 		if (ret)
 			continue;
 

src/libcamera/pipeline/rkisp1/rkisp1.cpp

@@ -81,7 +81,7 @@ private:
 	int createCamera(MediaEntity *sensor);
 	void bufferReady(Buffer *buffer);
 
-	std::shared_ptr<MediaDevice> media_;
+	MediaDevice *media_;
 	V4L2Subdevice *dphy_;
 	V4L2Subdevice *isp_;
 	V4L2Device *video_;
@@ -100,9 +100,6 @@ PipelineHandlerRkISP1::~PipelineHandlerRkISP1()
 	delete video_;
 	delete isp_;
 	delete dphy_;
-
-	if (media_)
-		media_->release();
 }
 
 /* -----------------------------------------------------------------------------
@@ -355,24 +352,21 @@ bool PipelineHandlerRkISP1::match(DeviceEnumerator *enumerator)
 	dm.add("rkisp1-input-params");
 	dm.add("rockchip-sy-mipi-dphy");
 
-	media_ = enumerator->search(dm);
+	media_ = acquireMediaDevice(enumerator, dm);
 	if (!media_)
 		return false;
 
-	media_->acquire();
-
 	/* Create the V4L2 subdevices we will need. */
-	dphy_ = V4L2Subdevice::fromEntityName(media_.get(),
-					      "rockchip-sy-mipi-dphy");
+	dphy_ = V4L2Subdevice::fromEntityName(media_, "rockchip-sy-mipi-dphy");
 	if (dphy_->open() < 0)
 		return false;
 
-	isp_ = V4L2Subdevice::fromEntityName(media_.get(), "rkisp1-isp-subdev");
+	isp_ = V4L2Subdevice::fromEntityName(media_, "rkisp1-isp-subdev");
 	if (isp_->open() < 0)
 		return false;
 
 	/* Locate and open the capture video node. */
-	video_ = V4L2Device::fromEntityName(media_.get(), "rkisp1_mainpath");
+	video_ = V4L2Device::fromEntityName(media_, "rkisp1_mainpath");
 	if (video_->open() < 0)
 		return false;
 

src/libcamera/pipeline/uvcvideo.cpp

@@ -24,7 +24,6 @@ class PipelineHandlerUVC : public PipelineHandler
 {
 public:
 	PipelineHandlerUVC(CameraManager *manager);
-	~PipelineHandlerUVC();
 
 	CameraConfiguration
 	streamConfiguration(Camera *camera,
@@ -69,21 +68,13 @@ private:
 		return static_cast<UVCCameraData *>(
 			PipelineHandler::cameraData(camera));
 	}
-
-	std::shared_ptr<MediaDevice> media_;
 };
 
 PipelineHandlerUVC::PipelineHandlerUVC(CameraManager *manager)
-	: PipelineHandler(manager), media_(nullptr)
+	: PipelineHandler(manager)
 {
 }
 
-PipelineHandlerUVC::~PipelineHandlerUVC()
-{
-	if (media_)
-		media_->release();
-}
-
 CameraConfiguration
 PipelineHandlerUVC::streamConfiguration(Camera *camera,
 					const std::vector<StreamUsage> &usages)
@@ -177,19 +168,17 @@ int PipelineHandlerUVC::queueRequest(Camera *camera, Request *request)
 
 bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 {
+	MediaDevice *media;
 	DeviceMatch dm("uvcvideo");
 
-	media_ = enumerator->search(dm);
-	if (!media_)
-		return false;
-
-	if (!media_->acquire())
+	media = acquireMediaDevice(enumerator, dm);
+	if (!media)
 		return false;
 
 	std::unique_ptr<UVCCameraData> data = utils::make_unique<UVCCameraData>(this);
 
 	/* Locate and open the default video node. */
-	for (MediaEntity *entity : media_->entities()) {
+	for (MediaEntity *entity : media->entities()) {
 		if (entity->flags() & MEDIA_ENT_FL_DEFAULT) {
 			data->video_ = new V4L2Device(entity);
 			break;
@@ -208,11 +197,11 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 
 	/* Create and register the camera. */
 	std::set<Stream *> streams{ &data->stream_ };
-	std::shared_ptr<Camera> camera = Camera::create(this, media_->model(), streams);
+	std::shared_ptr<Camera> camera = Camera::create(this, media->model(), streams);
 	registerCamera(std::move(camera), std::move(data));
 
 	/* Enable hot-unplug notifications. */
-	hotplugMediaDevice(media_.get());
+	hotplugMediaDevice(media);
 
 	return true;
 }

src/libcamera/pipeline/vimc.cpp

@@ -24,7 +24,6 @@ class PipelineHandlerVimc : public PipelineHandler
 {
 public:
 	PipelineHandlerVimc(CameraManager *manager);
-	~PipelineHandlerVimc();
 
 	CameraConfiguration
 	streamConfiguration(Camera *camera,
@@ -69,21 +68,13 @@ private:
 		return static_cast<VimcCameraData *>(
 			PipelineHandler::cameraData(camera));
 	}
-
-	std::shared_ptr<MediaDevice> media_;
 };
 
 PipelineHandlerVimc::PipelineHandlerVimc(CameraManager *manager)
-	: PipelineHandler(manager), media_(nullptr)
+	: PipelineHandler(manager)
 {
 }
 
-PipelineHandlerVimc::~PipelineHandlerVimc()
-{
-	if (media_)
-		media_->release();
-}
-
 CameraConfiguration
 PipelineHandlerVimc::streamConfiguration(Camera *camera,
 					 const std::vector<StreamUsage> &usages)
@@ -189,17 +180,14 @@ bool PipelineHandlerVimc::match(DeviceEnumerator *enumerator)
 	dm.add("RGB/YUV Input");
 	dm.add("Scaler");
 
-	media_ = enumerator->search(dm);
-	if (!media_)
-		return false;
-
-	if (!media_->acquire())
+	MediaDevice *media = acquireMediaDevice(enumerator, dm);
+	if (!media)
 		return false;
 
 	std::unique_ptr<VimcCameraData> data = utils::make_unique<VimcCameraData>(this);
 
 	/* Locate and open the capture video node. */
-	data->video_ = new V4L2Device(media_->getEntityByName("Raw Capture 1"));
+	data->video_ = new V4L2Device(media->getEntityByName("Raw Capture 1"));
 	if (data->video_->open())
 		return false;
 

src/libcamera/pipeline_handler.cpp

@@ -11,6 +11,7 @@
 #include <libcamera/camera.h>
 #include <libcamera/camera_manager.h>
 
+#include "device_enumerator.h"
 #include "log.h"
 #include "media_device.h"
 #include "utils.h"
@@ -116,6 +117,8 @@ PipelineHandler::PipelineHandler(CameraManager *manager)
 
 PipelineHandler::~PipelineHandler()
 {
+	for (std::shared_ptr<MediaDevice> media : mediaDevices_)
+		media->release();
 };
 
 /**
@@ -149,6 +152,35 @@ PipelineHandler::~PipelineHandler()
  * created, or false otherwise
  */
 
+/**
+ * \brief Search and acquire a MediDevice matching a device pattern
+ * \param[in] enumerator Enumerator containing all media devices in the system
+ * \param[in] dm Device match pattern
+ *
+ * Search the device \a enumerator for an available media device matching the
+ * device match pattern \a dm. Matching media device that have previously been
+ * acquired by MediaDevice::acquire() are not considered. If a match is found,
+ * the media device is acquired and returned. The caller shall not release the
+ * device explicitly, it will be automatically released when the pipeline
+ * handler is destroyed.
+ *
+ * \return A pointer to the matching MediaDevice, or nullptr if no match is found
+ */
+MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator,
+						 const DeviceMatch &dm)
+{
+	std::shared_ptr<MediaDevice> media = enumerator->search(dm);
+	if (!media)
+		return nullptr;
+
+	if (!media->acquire())
+		return nullptr;
+
+	mediaDevices_.push_back(media);
+
+	return media.get();
+}
+
 /**
  * \fn PipelineHandler::streamConfiguration()
  * \brief Retrieve a group of stream configurations for a specified camera