[media] media-device: add support for MEDIA_IOC_G_TOPOLOGY ioctl

Add support for the new MEDIA_IOC_G_TOPOLOGY ioctl, according
with the RFC for the MC next generation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/media-device.c

@@ -232,6 +232,156 @@ static long media_device_setup_link(struct media_device *mdev,
 	return ret;
 }
 
+static long __media_device_get_topology(struct media_device *mdev,
+				      struct media_v2_topology *topo)
+{
+	struct media_entity *entity;
+	struct media_interface *intf;
+	struct media_pad *pad;
+	struct media_link *link;
+	struct media_v2_entity uentity;
+	struct media_v2_interface uintf;
+	struct media_v2_pad upad;
+	struct media_v2_link ulink;
+	int ret = 0, i;
+
+	topo->topology_version = mdev->topology_version;
+
+	/* Get entities and number of entities */
+	i = 0;
+	media_device_for_each_entity(entity, mdev) {
+		i++;
+
+		if (ret || !topo->entities)
+			continue;
+
+		if (i > topo->num_entities) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		/* Copy fields to userspace struct if not error */
+		memset(&uentity, 0, sizeof(uentity));
+		uentity.id = entity->graph_obj.id;
+		strncpy(uentity.name, entity->name,
+			sizeof(uentity.name));
+
+		if (copy_to_user(&topo->entities[i - 1], &uentity, sizeof(uentity)))
+			ret = -EFAULT;
+	}
+	topo->num_entities = i;
+
+	/* Get interfaces and number of interfaces */
+	i = 0;
+	media_device_for_each_intf(intf, mdev) {
+		i++;
+
+		if (ret || !topo->interfaces)
+			continue;
+
+		if (i > topo->num_interfaces) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&uintf, 0, sizeof(uintf));
+
+		/* Copy intf fields to userspace struct */
+		uintf.id = intf->graph_obj.id;
+		uintf.intf_type = intf->type;
+		uintf.flags = intf->flags;
+
+		if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
+			struct media_intf_devnode *devnode;
+
+			devnode = intf_to_devnode(intf);
+
+			uintf.devnode.major = devnode->major;
+			uintf.devnode.minor = devnode->minor;
+		}
+
+		if (copy_to_user(&topo->interfaces[i - 1], &uintf, sizeof(uintf)))
+			ret = -EFAULT;
+	}
+	topo->num_interfaces = i;
+
+	/* Get pads and number of pads */
+	i = 0;
+	media_device_for_each_pad(pad, mdev) {
+		i++;
+
+		if (ret || !topo->pads)
+			continue;
+
+		if (i > topo->num_pads) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&upad, 0, sizeof(upad));
+
+		/* Copy pad fields to userspace struct */
+		upad.id = pad->graph_obj.id;
+		upad.entity_id = pad->entity->graph_obj.id;
+		upad.flags = pad->flags;
+
+		if (copy_to_user(&topo->pads[i - 1], &upad, sizeof(upad)))
+			ret = -EFAULT;
+	}
+	topo->num_pads = i;
+
+	/* Get links and number of links */
+	i = 0;
+	media_device_for_each_link(link, mdev) {
+		i++;
+
+		if (ret || !topo->links)
+			continue;
+
+		if (i > topo->num_links) {
+			ret = -ENOSPC;
+			continue;
+		}
+
+		memset(&ulink, 0, sizeof(ulink));
+
+		/* Copy link fields to userspace struct */
+		ulink.id = link->graph_obj.id;
+		ulink.source_id = link->gobj0->id;
+		ulink.sink_id = link->gobj1->id;
+		ulink.flags = link->flags;
+
+		if (media_type(link->gobj0) != MEDIA_GRAPH_PAD)
+			ulink.flags |= MEDIA_LNK_FL_INTERFACE_LINK;
+
+		if (copy_to_user(&topo->links[i - 1], &ulink, sizeof(ulink)))
+			ret = -EFAULT;
+	}
+	topo->num_links = i;
+
+	return ret;
+}
+
+static long media_device_get_topology(struct media_device *mdev,
+				      struct media_v2_topology __user *utopo)
+{
+	struct media_v2_topology ktopo;
+	int ret;
+
+	ret = copy_from_user(&ktopo, utopo, sizeof(ktopo));
+
+	if (ret < 0)
+		return ret;
+
+	ret = __media_device_get_topology(mdev, &ktopo);
+	if (ret < 0)
+		return ret;
+
+	ret = copy_to_user(utopo, &ktopo, sizeof(*utopo));
+
+	return ret;
+}
+
 static long media_device_ioctl(struct file *filp, unsigned int cmd,
 			       unsigned long arg)
 {
@@ -264,6 +414,13 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
 		mutex_unlock(&dev->graph_mutex);
 		break;
 
+	case MEDIA_IOC_G_TOPOLOGY:
+		mutex_lock(&dev->graph_mutex);
+		ret = media_device_get_topology(dev,
+				(struct media_v2_topology __user *)arg);
+		mutex_unlock(&dev->graph_mutex);
+		break;
+
 	default:
 		ret = -ENOIOCTLCMD;
 	}
@@ -312,6 +469,7 @@ static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
 	case MEDIA_IOC_DEVICE_INFO:
 	case MEDIA_IOC_ENUM_ENTITIES:
 	case MEDIA_IOC_SETUP_LINK:
+	case MEDIA_IOC_G_TOPOLOGY:
 		return media_device_ioctl(filp, cmd, arg);
 
 	case MEDIA_IOC_ENUM_LINKS32: