[media] media: Media device information query

Create the following ioctl and implement it at the media device level to
query device information.

- MEDIA_IOC_DEVICE_INFO: Query media device information

The ioctl and its data structure are defined in the new kernel header
linux/media.h available to userspace applications.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index d2bc809d7a2..92e0d4eb84b 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -22,13 +22,70 @@
 
 #include <linux/types.h>
 #include <linux/ioctl.h>
+#include <linux/media.h>
 
 #include <media/media-device.h>
 #include <media/media-devnode.h>
 #include <media/media-entity.h>
 
+/* -----------------------------------------------------------------------------
+ * Userspace API
+ */
+
+static int media_device_open(struct file *filp)
+{
+        return 0;
+}
+
+static int media_device_close(struct file *filp)
+{
+        return 0;
+}
+
+static int media_device_get_info(struct media_device *dev,
+                                 struct media_device_info __user *__info)
+{
+        struct media_device_info info;
+
+        memset(&info, 0, sizeof(info));
+
+        strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver));
+        strlcpy(info.model, dev->model, sizeof(info.model));
+        strlcpy(info.serial, dev->serial, sizeof(info.serial));
+        strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info));
+
+        info.media_version = MEDIA_API_VERSION;
+        info.hw_revision = dev->hw_revision;
+        info.driver_version = dev->driver_version;
+
+        return copy_to_user(__info, &info, sizeof(*__info));
+}
+
+static long media_device_ioctl(struct file *filp, unsigned int cmd,
+                               unsigned long arg)
+{
+        struct media_devnode *devnode = media_devnode_data(filp);
+        struct media_device *dev = to_media_device(devnode);
+        long ret;
+
+        switch (cmd) {
+        case MEDIA_IOC_DEVICE_INFO:
+                ret = media_device_get_info(dev,
+                                (struct media_device_info __user *)arg);
+                break;
+
+        default:
+                ret = -ENOIOCTLCMD;
+        }
+
+        return ret;
+}
+
 static const struct media_file_operations media_device_fops = {
         .owner = THIS_MODULE,
+        .open = media_device_open,
+        .ioctl = media_device_ioctl,
+        .release = media_device_close,
 };
 
 /* -----------------------------------------------------------------------------