From patchwork Tue Nov 30 14:15:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 517334 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 DFBB5C433FE for ; Tue, 30 Nov 2021 14:17:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242170AbhK3OUc (ORCPT ); Tue, 30 Nov 2021 09:20:32 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:41006 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242112AbhK3OUP (ORCPT ); Tue, 30 Nov 2021 09:20:15 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 1CD191AEF; Tue, 30 Nov 2021 15:16:54 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1638281814; bh=pup5nN9n5Z7noq+cLFddgdum0bunoz4HTnRrCEbPVoI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ET4W8za6gTzuFVXrA+2RS6I3CakXszrhkV0ghGl1oXzXfmm7vR16tmi1yU4GTdtQR +vVhRmjMjPofmyxwEe3GKypBSoWbGGF2dEVG/d4+dVznLJ0+leHevFtSo+fr1gOtan Kmaj0Wm/XRDHtPC2lxvb9v5Zd6heFMyyyHDRmc9M= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH v10 27/38] media: Documentation: Add GS_ROUTING documentation Date: Tue, 30 Nov 2021 16:15:25 +0200 Message-Id: <20211130141536.891878-28-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211130141536.891878-1-tomi.valkeinen@ideasonboard.com> References: <20211130141536.891878-1-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 | 150 ++++++++++++++++++ 3 files changed, 153 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..a0d9c79e162f --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst @@ -0,0 +1,150 @@ +.. 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:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_ROUTING, struct v4l2_subdev_routing *argp ) + :name: VIDIOC_SUBDEV_G_ROUTING + +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_ROUTING, struct v4l2_subdev_routing *argp ) + :name: VIDIOC_SUBDEV_S_ROUTING + + +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 mut reconfigure all streams after calling the ioctl +with e.g. ``VIDIOC_SUBDEV_S_FMT``. + +A special case for routing are routes marked with +``V4L2_SUBDEV_ROUTE_FL_SOURCE`` flag. These routes are used to describe +source endpoints on sensors and the sink fields are unused. + +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. + * - V4L2_SUBDEV_ROUTE_FL_IMMUTABLE + - 1 + - The route is immutable. Set by the driver. + * - V4L2_SUBDEV_ROUTE_FL_SOURCE + - 2 + - The route is a source route, and the ``sink_pad`` and ``sink_stream`` + fields are unused. Set by the driver. + +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 number of provided route entries is less than the available ones. + +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.