Commit f75c431e authored by Jacopo Mondi's avatar Jacopo Mondi Committed by Mauro Carvalho Chehab
Browse files

media: v4l2-dev: Add v4l2_device_register_ro_subdev_node() 



Add to the V4L2 core a function to register device nodes for video
subdevices in read-only mode.

Registering a device node in read-only mode is useful to expose to
userspace the current sub-device configuration, without allowing
application to change it by using the V4L2 subdevice ioctls.

Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 3fb0ee8b

drivers/media/v4l2-core/v4l2-device.c

+5 −2
Original line number Diff line number Diff line
@@ -186,7 +186,8 @@ static void v4l2_device_release_subdev_node(struct video_device *vdev) 
	kfree(vdev);

}



int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)

int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,

					bool read_only)

{

	struct video_device *vdev;

	struct v4l2_subdev *sd;
@@ -215,6 +216,8 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) 
		vdev->fops = &v4l2_subdev_fops;

		vdev->release = v4l2_device_release_subdev_node;

		vdev->ctrl_handler = sd->ctrl_handler;

		if (read_only)

			set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);

		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,

					      sd->owner);

		if (err < 0) {
@@ -252,7 +255,7 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) 


	return err;

}

EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);

EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);



void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)

{

drivers/media/v4l2-core/v4l2-subdev.c

+19 −0
Original line number Diff line number Diff line
@@ -331,6 +331,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	struct v4l2_fh *vfh = file->private_data;

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)

	struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);

	bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);

#endif

	int rval;
@@ -477,6 +478,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	case VIDIOC_SUBDEV_S_FMT: {

		struct v4l2_subdev_format *format = arg;



		if (format->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)

			return -EPERM;



		memset(format->reserved, 0, sizeof(format->reserved));

		memset(format->format.reserved, 0, sizeof(format->format.reserved));

		return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
@@ -504,6 +508,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
		struct v4l2_subdev_crop *crop = arg;

		struct v4l2_subdev_selection sel;



		if (crop->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)

			return -EPERM;



		memset(crop->reserved, 0, sizeof(crop->reserved));

		memset(&sel, 0, sizeof(sel));

		sel.which = crop->which;
@@ -545,6 +552,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {

		struct v4l2_subdev_frame_interval *fi = arg;



		if (ro_subdev)

			return -EPERM;



		memset(fi->reserved, 0, sizeof(fi->reserved));

		return v4l2_subdev_call(sd, video, s_frame_interval, arg);

	}
@@ -568,6 +578,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	case VIDIOC_SUBDEV_S_SELECTION: {

		struct v4l2_subdev_selection *sel = arg;



		if (sel->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)

			return -EPERM;



		memset(sel->reserved, 0, sizeof(sel->reserved));

		return v4l2_subdev_call(

			sd, pad, set_selection, subdev_fh->pad, sel);
@@ -604,6 +617,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
		return v4l2_subdev_call(sd, video, g_dv_timings, arg);



	case VIDIOC_SUBDEV_S_DV_TIMINGS:

		if (ro_subdev)

			return -EPERM;



		return v4l2_subdev_call(sd, video, s_dv_timings, arg);



	case VIDIOC_SUBDEV_G_STD:
@@ -612,6 +628,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	case VIDIOC_SUBDEV_S_STD: {

		v4l2_std_id *std = arg;



		if (ro_subdev)

			return -EPERM;



		return v4l2_subdev_call(sd, video, s_std, *std);

	}

include/media/v4l2-dev.h

+7 −0
Original line number Diff line number Diff line
@@ -82,11 +82,18 @@ struct v4l2_ctrl_handler; 
 *	but the old crop API will still work as expected in order to preserve

 *	backwards compatibility.

 *	Never set this flag for new drivers.

 * @V4L2_FL_SUBDEV_RO_DEVNODE:

 *	indicates that the video device node is registered in read-only mode.

 *	The flag only applies to device nodes registered for sub-devices, it is

 *	set by the core when the sub-devices device nodes are registered with

 *	v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl

 *	handler to restrict access to some ioctl calls.

 */

enum v4l2_video_device_flags {

	V4L2_FL_REGISTERED		= 0,

	V4L2_FL_USES_V4L2_FH		= 1,

	V4L2_FL_QUIRK_INVERTED_CROP	= 2,

	V4L2_FL_SUBDEV_RO_DEVNODE	= 3,

};



/* Priority helper functions */

include/media/v4l2-device.h

+46 −4
Original line number Diff line number Diff line
@@ -174,14 +174,56 @@ int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, 
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);



/**

 * v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs

 *	of the v4l2 device that are marked with

 *	the %V4L2_SUBDEV_FL_HAS_DEVNODE flag.

 * __v4l2_device_register_ro_subdev_nodes - Registers device nodes for

 *      all subdevs of the v4l2 device that are marked with the

 *      %V4L2_SUBDEV_FL_HAS_DEVNODE flag.

 *

 * @v4l2_dev: pointer to struct v4l2_device

 * @read_only: subdevices read-only flag. True to register the subdevices

 *	device nodes in read-only mode, false to allow full access to the

 *	subdevice userspace API.

 */

int __must_check

v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);

__v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,

				    bool read_only);



/**

 * v4l2_device_register_subdev_nodes - Registers subdevices device nodes with

 *	unrestricted access to the subdevice userspace operations

 *

 * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation

 * for more details.

 *

 * @v4l2_dev: pointer to struct v4l2_device

 */

static inline int __must_check

v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)

{

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)

	return __v4l2_device_register_subdev_nodes(v4l2_dev, false);

#else

	return 0;

#endif

}



/**

 * v4l2_device_register_ro_subdev_nodes - Registers subdevices device nodes

 *	in read-only mode

 *

 * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation

 * for more details.

 *

 * @v4l2_dev: pointer to struct v4l2_device

 */

static inline int __must_check

v4l2_device_register_ro_subdev_nodes(struct v4l2_device *v4l2_dev)

{

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)

	return __v4l2_device_register_subdev_nodes(v4l2_dev, true);

#else

	return 0;

#endif

}



/**

 * v4l2_subdev_notify - Sends a notification to v4l2_device.