From patchwork Thu Dec 15 12:16:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 13074134 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D78DAC4167B for ; Thu, 15 Dec 2022 12:17:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230202AbiLOMRP (ORCPT ); Thu, 15 Dec 2022 07:17:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230109AbiLOMRN (ORCPT ); Thu, 15 Dec 2022 07:17:13 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70EA02E9DE; Thu, 15 Dec 2022 04:17:12 -0800 (PST) Received: from desky.lan (91-154-32-225.elisa-laajakaista.fi [91.154.32.225]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E568218A1; Thu, 15 Dec 2022 13:17:08 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1671106629; bh=LR7vKOSIPTCulYfYoXP0H84qy+/BWwcbk50Nar0L1aw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e8e4B8sN7nDgN4kkzlNFydckWpwX6NjoMtGM2rzM6SsrwfL77CWoATyCO8k898Y1H 7IVw4eYadNJDWWVfvqpQ57ue2QNO9RfyGvgPqOI+gQ1lB5IfksoiYBU2hEKcrJvDE1 L3irBk/muv/DeqmG/uXsA//p35OuNWefolSS4BD0= From: Tomi Valkeinen To: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , satish.nagireddy@getcruise.com, Tomasz Figa Cc: Tomi Valkeinen Subject: [PATCH v16 04/20] media: Documentation: Add GS_ROUTING documentation Date: Thu, 15 Dec 2022 14:16:18 +0200 Message-Id: <20221215121634.287100-5-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221215121634.287100-1-tomi.valkeinen@ideasonboard.com> References: <20221215121634.287100-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Jacopo Mondi Add documentation for VIDIOC_SUBDEV_G/S_ROUTING ioctl and add description of multiplexed media pads and internal routing to the V4L2-subdev documentation section. Signed-off-by: Jacopo Mondi Signed-off-by: Tomi Valkeinen Reviewed-by: Hans Verkuil --- .../userspace-api/media/v4l/dev-subdev.rst | 2 + .../userspace-api/media/v4l/user-func.rst | 1 + .../media/v4l/vidioc-subdev-g-routing.rst | 147 ++++++++++++++++++ 3 files changed, 150 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst index fd1de0a73a9f..a67c2749089a 100644 --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst @@ -29,6 +29,8 @@ will feature a character device node on which ioctls can be called to - negotiate image formats on individual pads +- inspect and modify internal data routing between pads of the same entity + Sub-device character device nodes, conventionally named ``/dev/v4l-subdev*``, use major number 81. diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst index 53e604bd7d60..228c1521f190 100644 --- a/Documentation/userspace-api/media/v4l/user-func.rst +++ b/Documentation/userspace-api/media/v4l/user-func.rst @@ -70,6 +70,7 @@ Function Reference vidioc-subdev-g-crop vidioc-subdev-g-fmt vidioc-subdev-g-frame-interval + vidioc-subdev-g-routing vidioc-subdev-g-selection vidioc-subdev-querycap vidioc-subscribe-event diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst new file mode 100644 index 000000000000..68ca343c3b44 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst @@ -0,0 +1,147 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _VIDIOC_SUBDEV_G_ROUTING: + +****************************************************** +ioctl VIDIOC_SUBDEV_G_ROUTING, VIDIOC_SUBDEV_S_ROUTING +****************************************************** + +Name +==== + +VIDIOC_SUBDEV_G_ROUTING - VIDIOC_SUBDEV_S_ROUTING - Get or set routing between streams of media pads in a media entity. + + +Synopsis +======== + +.. c:macro:: VIDIOC_SUBDEV_G_ROUTING + +``int ioctl(int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp)`` + +.. c:macro:: VIDIOC_SUBDEV_S_ROUTING + +``int ioctl(int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() `. + +``argp`` + Pointer to struct :c:type:`v4l2_subdev_routing`. + + +Description +=========== + +These ioctls are used to get and set the routing in a media entity. +The routing configuration determines the flows of data inside an entity. + +Drivers report their current routing tables using the +``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes +with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and +setting or clearing flags of the ``flags`` field of a +struct :c:type:`v4l2_subdev_route`. + +All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This +means that the userspace must reconfigure all streams after calling the ioctl +with e.g. ``VIDIOC_SUBDEV_S_FMT``. + +Only subdevices which have both sink and source pads can support routing. + +When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application +provided ``num_routes`` is not big enough to contain all the available routes +the subdevice exposes, drivers return the ENOSPC error code and adjust the +value of the ``num_routes`` field. Application should then reserve enough memory +for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again. + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_subdev_routing + +.. flat-table:: struct v4l2_subdev_routing + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``which`` + - Format to modified, from enum + :ref:`v4l2_subdev_format_whence `. + * - struct :c:type:`v4l2_subdev_route` + - ``routes[]`` + - Array of struct :c:type:`v4l2_subdev_route` entries + * - __u32 + - ``num_routes`` + - Number of entries of the routes array + * - __u32 + - ``reserved``\ [5] + - Reserved for future extensions. Applications and drivers must set + the array to zero. + +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| + +.. c:type:: v4l2_subdev_route + +.. flat-table:: struct v4l2_subdev_route + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + * - __u32 + - ``sink_pad`` + - Sink pad number. + * - __u32 + - ``sink_stream`` + - Sink pad stream number. + * - __u32 + - ``source_pad`` + - Source pad number. + * - __u32 + - ``source_stream`` + - Source pad stream number. + * - __u32 + - ``flags`` + - Route enable/disable flags + :ref:`v4l2_subdev_routing_flags `. + * - __u32 + - ``reserved``\ [5] + - Reserved for future extensions. Applications and drivers must set + the array to zero. + +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}| + +.. _v4l2-subdev-routing-flags: + +.. flat-table:: enum v4l2_subdev_routing_flags + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - V4L2_SUBDEV_ROUTE_FL_ACTIVE + - 0 + - The route is enabled. Set by applications. + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes ` chapter. + +ENOSPC + The application provided ``num_routes`` is not big enough to contain + all the available routes the subdevice exposes. + +EINVAL + The sink or source pad identifiers reference a non-existing pad, or reference + pads of different types (ie. the sink_pad identifiers refers to a source pad) + or the sink or source stream identifiers reference a non-existing stream on + the sink or source pad. + +E2BIG + The application provided ``num_routes`` for ``VIDIOC_SUBDEV_S_ROUTING`` is + larger than the number of routes the driver can handle.