[media] media: Links setup

Create the following ioctl and implement it at the media device level to
setup links.

- MEDIA_IOC_SETUP_LINK: Modify the properties of a given link

The only property that can currently be modified is the ENABLED link
flag to enable/disable a link. Links marked with the IMMUTABLE link flag
can not be enabled or disabled.

Enabling or disabling a link has effects on entities' use count. Those
changes are automatically propagated through the graph.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 648a9d892ac1..16b70b4412f7 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -172,6 +172,44 @@ static long media_device_enum_links(struct media_device *mdev,
         return 0;
 }
 
+static long media_device_setup_link(struct media_device *mdev,
+                                    struct media_link_desc __user *_ulink)
+{
+        struct media_link *link = NULL;
+        struct media_link_desc ulink;
+        struct media_entity *source;
+        struct media_entity *sink;
+        int ret;
+
+        if (copy_from_user(&ulink, _ulink, sizeof(ulink)))
+                return -EFAULT;
+
+        /* Find the source and sink entities and link.
+         */
+        source = find_entity(mdev, ulink.source.entity);
+        sink = find_entity(mdev, ulink.sink.entity);
+
+        if (source == NULL || sink == NULL)
+                return -EINVAL;
+
+        if (ulink.source.index >= source->num_pads ||
+            ulink.sink.index >= sink->num_pads)
+                return -EINVAL;
+
+        link = media_entity_find_link(&source->pads[ulink.source.index],
+                                      &sink->pads[ulink.sink.index]);
+        if (link == NULL)
+                return -EINVAL;
+
+        /* Setup the link on both entities. */
+        ret = __media_entity_setup_link(link, ulink.flags);
+
+        if (copy_to_user(_ulink, &ulink, sizeof(ulink)))
+                return -EFAULT;
+
+        return ret;
+}
+
 static long media_device_ioctl(struct file *filp, unsigned int cmd,
                                unsigned long arg)
 {
@@ -197,6 +235,13 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
                 mutex_unlock(&dev->graph_mutex);
                 break;
 
+        case MEDIA_IOC_SETUP_LINK:
+                mutex_lock(&dev->graph_mutex);
+                ret = media_device_setup_link(dev,
+                                (struct media_link_desc __user *)arg);
+                mutex_unlock(&dev->graph_mutex);
+                break;
+
         default:
                 ret = -ENOIOCTLCMD;
         }