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Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0638-Documentation-media-Document-read-only-subdevice.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0638-Documentation-media-Document-read-only-subdevice.patch | 217 |
1 files changed, 0 insertions, 217 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0638-Documentation-media-Document-read-only-subdevice.patch b/target/linux/bcm27xx/patches-5.4/950-0638-Documentation-media-Document-read-only-subdevice.patch deleted file mode 100644 index 1983334ae1..0000000000 --- a/target/linux/bcm27xx/patches-5.4/950-0638-Documentation-media-Document-read-only-subdevice.patch +++ /dev/null @@ -1,217 +0,0 @@ -From c1a630e792140b4791bad84974e31b4a1cf09b1b Mon Sep 17 00:00:00 2001 -From: Jacopo Mondi <jacopo@jmondi.org> -Date: Tue, 7 Apr 2020 17:21:56 +0200 -Subject: [PATCH] Documentation: media: Document read-only subdevice - -Document a new kAPI function to register subdev device nodes in read only -mode and for each affected ioctl report how access is restricted. - -Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> -Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> ---- - Documentation/media/kapi/v4l2-subdev.rst | 44 +++++++++++++++++++ - Documentation/media/uapi/v4l/dev-subdev.rst | 5 +++ - .../media/uapi/v4l/vidioc-g-dv-timings.rst | 6 +++ - Documentation/media/uapi/v4l/vidioc-g-std.rst | 6 +++ - .../media/uapi/v4l/vidioc-subdev-g-crop.rst | 9 ++++ - .../media/uapi/v4l/vidioc-subdev-g-fmt.rst | 8 ++++ - .../v4l/vidioc-subdev-g-frame-interval.rst | 8 ++++ - .../uapi/v4l/vidioc-subdev-g-selection.rst | 8 ++++ - 8 files changed, 94 insertions(+) - ---- a/Documentation/media/kapi/v4l2-subdev.rst -+++ b/Documentation/media/kapi/v4l2-subdev.rst -@@ -332,6 +332,50 @@ Private ioctls - All ioctls not in the above list are passed directly to the sub-device - driver through the core::ioctl operation. - -+Read-only sub-device userspace API -+---------------------------------- -+ -+Bridge drivers that control their connected subdevices through direct calls to -+the kernel API realized by :c:type:`v4l2_subdev_ops` structure do not usually -+want userspace to be able to change the same parameters through the subdevice -+device node and thus do not usually register any. -+ -+It is sometimes useful to report to userspace the current subdevice -+configuration through a read-only API, that does not permit applications to -+change to the device parameters but allows interfacing to the subdevice device -+node to inspect them. -+ -+For instance, to implement cameras based on computational photography, userspace -+needs to know the detailed camera sensor configuration (in terms of skipping, -+binning, cropping and scaling) for each supported output resolution. To support -+such use cases, bridge drivers may expose the subdevice operations to userspace -+through a read-only API. -+ -+To create a read-only device node for all the subdevices registered with the -+``V4L2_SUBDEV_FL_HAS_DEVNODE`` set, the :c:type:`v4l2_device` driver should call -+:c:func:`v4l2_device_register_ro_subdev_nodes`. -+ -+Access to the following ioctls for userspace applications is restricted on -+sub-device device nodes registered with -+:c:func:`v4l2_device_register_ro_subdev_nodes`. -+ -+``VIDIOC_SUBDEV_S_FMT``, -+``VIDIOC_SUBDEV_S_CROP``, -+``VIDIOC_SUBDEV_S_SELECTION``: -+ -+ These ioctls are only allowed on a read-only subdevice device node -+ for the :ref:`V4L2_SUBDEV_FORMAT_TRY <v4l2-subdev-format-whence>` -+ formats and selection rectangles. -+ -+``VIDIOC_SUBDEV_S_FRAME_INTERVAL``, -+``VIDIOC_SUBDEV_S_DV_TIMINGS``, -+``VIDIOC_SUBDEV_S_STD``: -+ -+ These ioctls are not allowed on a read-only subdevice node. -+ -+In case the ioctl is not allowed, or the format to modify is set to -+``V4L2_SUBDEV_FORMAT_ACTIVE``, the core returns a negative error code and -+the errno variable is set to ``-EPERM``. - - I2C sub-device drivers - ---------------------- ---- a/Documentation/media/uapi/v4l/dev-subdev.rst -+++ b/Documentation/media/uapi/v4l/dev-subdev.rst -@@ -39,6 +39,11 @@ will feature a character device node on - Sub-device character device nodes, conventionally named - ``/dev/v4l-subdev*``, use major number 81. - -+Drivers may opt to limit the sub-device character devices to only expose -+operations that do not modify the device state. In such a case the sub-devices -+are referred to as ``read-only`` in the rest of this documentation, and the -+related restrictions are documented in individual ioctls. -+ - - Controls - ======== ---- a/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst -+++ b/Documentation/media/uapi/v4l/vidioc-g-dv-timings.rst -@@ -57,6 +57,10 @@ pointer to the struct :c:type:`v4l2_dv_t - structure as argument. If the ioctl is not supported or the timing - values are not correct, the driver returns ``EINVAL`` error code. - -+Calling ``VIDIOC_SUBDEV_S_DV_TIMINGS`` on a subdev device node that has been -+registered in read-only mode is not allowed. An error is returned and the errno -+variable is set to ``-EPERM``. -+ - The ``linux/v4l2-dv-timings.h`` header can be used to get the timings of - the formats in the :ref:`cea861` and :ref:`vesadmt` standards. If - the current input or output does not support DV timings (e.g. if -@@ -81,6 +85,8 @@ ENODATA - EBUSY - The device is busy and therefore can not change the timings. - -+EPERM -+ ``VIDIOC_SUBDEV_S_DV_TIMINGS`` has been called on a read-only subdevice. - - .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| - ---- a/Documentation/media/uapi/v4l/vidioc-g-std.rst -+++ b/Documentation/media/uapi/v4l/vidioc-g-std.rst -@@ -66,6 +66,9 @@ video timings (e.g. if :ref:`VIDIOC_ENUM - does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is - returned. - -+Calling ``VIDIOC_SUBDEV_S_STD`` on a subdev device node that has been registered -+in read-only mode is not allowed. An error is returned and the errno variable is -+set to ``-EPERM``. - - Return Value - ============ -@@ -79,3 +82,6 @@ EINVAL - - ENODATA - Standard video timings are not supported for this input or output. -+ -+EPERM -+ ``VIDIOC_SUBDEV_S_STD`` has been called on a read-only subdevice. ---- a/Documentation/media/uapi/v4l/vidioc-subdev-g-crop.rst -+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-crop.rst -@@ -73,6 +73,11 @@ crop rectangles and stored in the sub-de - applications querying the same sub-device would thus not interact with - each other. - -+If the subdev device node has been registered in read-only mode, calls to -+``VIDIOC_SUBDEV_S_CROP`` are only valid if the ``which`` field is set to -+``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno -+variable is set to ``-EPERM``. -+ - Drivers must not return an error solely because the requested crop - rectangle doesn't match the device capabilities. They must instead - modify the rectangle to match what the hardware can provide. The -@@ -123,3 +128,7 @@ EINVAL - references a non-existing pad, the ``which`` field references a - non-existing format, or cropping is not supported on the given - subdev pad. -+ -+EPERM -+ The ``VIDIOC_SUBDEV_S_CROP`` ioctl has been called on a read-only subdevice -+ and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``. ---- a/Documentation/media/uapi/v4l/vidioc-subdev-g-fmt.rst -+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-fmt.rst -@@ -78,6 +78,11 @@ current links configuration or sub-devic - a low-pass noise filter might crop pixels at the frame boundaries, - modifying its output frame size. - -+If the subdev device node has been registered in read-only mode, calls to -+``VIDIOC_SUBDEV_S_FMT`` are only valid if the ``which`` field is set to -+``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno -+variable is set to ``-EPERM``. -+ - Drivers must not return an error solely because the requested format - doesn't match the device capabilities. They must instead modify the - format to match what the hardware can provide. The modified format -@@ -146,6 +151,9 @@ EINVAL - ``pad`` references a non-existing pad, or the ``which`` field - references a non-existing format. - -+EPERM -+ The ``VIDIOC_SUBDEV_S_FMT`` ioctl has been called on a read-only subdevice -+ and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``. - - ============ - ---- a/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst -+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-frame-interval.rst -@@ -65,6 +65,10 @@ struct - contains the current frame interval as would be returned by a - ``VIDIOC_SUBDEV_G_FRAME_INTERVAL`` call. - -+Calling ``VIDIOC_SUBDEV_S_FRAME_INTERVAL`` on a subdev device node that has been -+registered in read-only mode is not allowed. An error is returned and the errno -+variable is set to ``-EPERM``. -+ - Drivers must not return an error solely because the requested interval - doesn't match the device capabilities. They must instead modify the - interval to match what the hardware can provide. The modified interval -@@ -118,3 +122,7 @@ EINVAL - :c:type:`v4l2_subdev_frame_interval` - ``pad`` references a non-existing pad, or the pad doesn't support - frame intervals. -+ -+EPERM -+ The ``VIDIOC_SUBDEV_S_FRAME_INTERVAL`` ioctl has been called on a read-only -+ subdevice. ---- a/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst -+++ b/Documentation/media/uapi/v4l/vidioc-subdev-g-selection.rst -@@ -53,6 +53,10 @@ function of the crop API, and more, are - See :ref:`subdev` for more information on how each selection target - affects the image processing pipeline inside the subdevice. - -+If the subdev device node has been registered in read-only mode, calls to -+``VIDIOC_SUBDEV_S_SELECTION`` are only valid if the ``which`` field is set to -+``V4L2_SUBDEV_FORMAT_TRY``, otherwise an error is returned and the errno -+variable is set to ``-EPERM``. - - Types of selection targets - -------------------------- -@@ -123,3 +127,7 @@ EINVAL - ``pad`` references a non-existing pad, the ``which`` field - references a non-existing format, or the selection target is not - supported on the given subdev pad. -+ -+EPERM -+ The ``VIDIOC_SUBDEV_S_SELECTION`` ioctl has been called on a read-only -+ subdevice and the ``which`` field is set to ``V4L2_SUBDEV_FORMAT_ACTIVE``. |