1 files changed, 131 insertions, 4 deletions

diff --git a/src/libcamera/device_enumerator_udev.cpp b/src/libcamera/device_enumerator_udev.cpp
index 86f6ca18..40853e77 100644
--- a/src/libcamera/device_enumerator_udev.cpp
+++ b/src/libcamera/device_enumerator_udev.cpp
@@ -7,6 +7,10 @@
 
 #include "device_enumerator_udev.h"
 
+#include <algorithm>
+#include <list>
+#include <map>
+
 #include <fcntl.h>
 #include <libudev.h>
 #include <string.h>
@@ -17,6 +21,7 @@
 #include <libcamera/event_notifier.h>
 
 #include "log.h"
+#include "media_device.h"
 
 namespace libcamera {
 
@@ -57,9 +62,40 @@ int DeviceEnumeratorUdev::init()
 	if (ret < 0)
 		return ret;
 
+	ret = udev_monitor_filter_add_match_subsystem_devtype(monitor_, "video4linux",
+							      nullptr);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
+int DeviceEnumeratorUdev::addUdevDevice(struct udev_device *dev)
+{
+	const char *subsystem = udev_device_get_subsystem(dev);
+	if (!subsystem)
+		return -ENODEV;
+
+	if (!strcmp(subsystem, "media")) {
+		std::shared_ptr<MediaDevice> media =
+			createDevice(udev_device_get_devnode(dev));
+		if (!media)
+			return -ENODEV;
+
+		int ret = populateMediaDevice(media);
+		if (ret == 0)
+			addDevice(media);
+		return 0;
+	}
+
+	if (!strcmp(subsystem, "video4linux")) {
+		addV4L2Device(udev_device_get_devnum(dev));
+		return 0;
+	}
+
+	return -ENODEV;
+}
+
 int DeviceEnumeratorUdev::enumerate()
 {
 	struct udev_enumerate *udev_enum = nullptr;
@@ -74,6 +110,14 @@ int DeviceEnumeratorUdev::enumerate()
 	if (ret < 0)
 		goto done;
 
+	ret = udev_enumerate_add_match_subsystem(udev_enum, "video4linux");
+	if (ret < 0)
+		goto done;
+
+	ret = udev_enumerate_add_match_is_initialized(udev_enum);
+	if (ret < 0)
+		goto done;
+
 	ret = udev_enumerate_scan_devices(udev_enum);
 	if (ret < 0)
 		goto done;
@@ -102,10 +146,12 @@ int DeviceEnumeratorUdev::enumerate()
 			goto done;
 		}
 
-		addDevice(devnode);
-
+		ret = addUdevDevice(dev);
 		udev_device_unref(dev);
+		if (ret < 0)
+			break;
 	}
+
 done:
 	udev_enumerate_unref(udev_enum);
 	if (ret < 0)
@@ -122,6 +168,43 @@ done:
 	return 0;
 }
 
+int DeviceEnumeratorUdev::populateMediaDevice(const std::shared_ptr<MediaDevice> &media)
+{
+	unsigned int pendingNodes = 0;
+	int ret;
+
+	/* Associate entities to device node paths. */
+	for (MediaEntity *entity : media->entities()) {
+		if (entity->deviceMajor() == 0 && entity->deviceMinor() == 0)
+			continue;
+
+		std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
+							  entity->deviceMinor());
+		dev_t devnum = makedev(entity->deviceMajor(),
+				       entity->deviceMinor());
+
+		/* Take device from orphan list first, if it is in the list. */
+		if (std::find(orphans_.begin(), orphans_.end(), devnum) != orphans_.end()) {
+			if (deviceNode.empty())
+				return -EINVAL;
+
+			ret = entity->setDeviceNode(deviceNode);
+			if (ret)
+				return ret;
+
+			orphans_.remove(devnum);
+			continue;
+		}
+
+		deps_[media].push_back(devnum);
+		devnumToDevice_[devnum] = media;
+		devnumToEntity_[devnum] = entity;
+		pendingNodes++;
+	}
+
+	return pendingNodes;
+}
+
 std::string DeviceEnumeratorUdev::lookupDeviceNode(int major, int minor)
 {
 	struct udev_device *device;
@@ -143,6 +226,48 @@ std::string DeviceEnumeratorUdev::lookupDeviceNode(int major, int minor)
 	return deviceNode;
 }
 
+/**
+ * \brief Add a V4L2 device to the media device that it belongs to
+ * \param[in] devnum major:minor number of V4L2 device to add, as a dev_t
+ *
+ * Add V4L2 device identified by \a devnum to the MediaDevice that it belongs
+ * to, if such a MediaDevice has been created. Otherwise add the V4L2 device
+ * to the orphan list. If the V4L2 device is added to a MediaDevice, and it is
+ * the last V4L2 device that the MediaDevice needs, then the MediaDevice is
+ * added to the DeviceEnumerator, where it is available for pipeline handlers.
+ *
+ * \return 0 on success or a negative error code otherwise
+ */
+int DeviceEnumeratorUdev::addV4L2Device(dev_t devnum)
+{
+	MediaEntity *entity = devnumToEntity_[devnum];
+	if (!entity) {
+		orphans_.push_back(devnum);
+		return 0;
+	}
+
+	std::string deviceNode = lookupDeviceNode(entity->deviceMajor(),
+						  entity->deviceMinor());
+	if (deviceNode.empty())
+		return -EINVAL;
+
+	int ret = entity->setDeviceNode(deviceNode);
+	if (ret)
+		return ret;
+
+	std::shared_ptr<MediaDevice> media = devnumToDevice_[devnum];
+	deps_[media].remove(devnum);
+	devnumToDevice_.erase(devnum);
+	devnumToEntity_.erase(devnum);
+
+	if (deps_[media].empty()) {
+		addDevice(media);
+		deps_.erase(media);
+	}
+
+	return 0;
+}
+
 void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
 {
 	struct udev_device *dev = udev_monitor_receive_device(monitor_);
@@ -153,9 +278,11 @@ void DeviceEnumeratorUdev::udevNotify(EventNotifier *notifier)
 		<< action << " device " << udev_device_get_devnode(dev);
 
 	if (action == "add") {
-		addDevice(deviceNode);
+		addUdevDevice(dev);
 	} else if (action == "remove") {
-		removeDevice(deviceNode);
+		const char *subsystem = udev_device_get_subsystem(dev);
+		if (subsystem && !strcmp(subsystem, "media"))
+			removeDevice(deviceNode);
 	}
 
 	udev_device_unref(dev);