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* media: mc: entity: Fix minor issues in comments and documentationLaurent Pinchart2023-02-061-6/+4
| | | | | | | | | | | | | | | | Commit ae219872834a ("media: mc: entity: Rewrite media_pipeline_start()") incorrectly referred to entity instead of pad in a comment, and forgot to update a second comment accordingly when moving the pipe from entity to pad. Furthermore, it didn't properly reflow the documentation text it updated. Fix those small issues. Fixes: ae219872834a ("media: mc: entity: Rewrite media_pipeline_start()") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: mc: entity: Rewrite media_pipeline_start()Laurent Pinchart2022-09-241-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Note: the code is mostly from Laurent but the patch description is from Tomi] The media_pipeline_start() and media_pipeline_stop() functions use the media graph walk API to traverse the graph and validate the pipeline. The graph walk traverses the media graph following links between the entities. Also, while the pipeline can't change between the start and stop calls, the graph is walked again from scratch at stop time, or any time a driver needs to inspect the pipeline. With the upcoming multiplexed streams support we will need a bit more intelligent pipeline construction, as e.g. two independent streams may be passing through a single entity via separate pads in which case those pads should not be part of the same pipeline. This patch essentially rewrites the media_pipeline_start/stop so that a pipeline is defined as a set of pads instead of entities and the media graph traversal considers the pad interdependencies when choosing which links to follow. Currently all the entity's pads are considered as interdependent. This means that the behavior with all the current drivers stays the same, but in the future we can define a more fine-grained pipeline construction. Additionally the media pipeline's pads are cached at media_pipeline_start() time, and re-used at media_pipeline_stop() which avoid the need to re-walk the whole graph as the previous implementation did. Also, caching pads in the pipeline can serve in the future as the foundation to provide a better API than the media graph walk to drivers to iterate over pads and entities in the pipeline. Note that the old media_pipeline_start/stop used the media graph walk API. The new version does not use the media graph walk API, but instead a new implementation. There are two reasons for not changing the graph walk: it proved to be rather difficult to change the graph walk to have the features implemented in this patch, and second, this keeps the backward compatibility of the graph walk as there are users of the graph walk API The long term plan is that all the existing code would be converted to use the new cached pipeline, thus allowing us to remove the graph walk. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: Documentation: mc: add definitions for stream and pipelineTomi Valkeinen2022-09-241-0/+12
| | | | | | | | | | The doc talks about streams and pipelines, but doesn't really define them. This is an attempt to define them according to my understanding. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: Documentation: mc-core: Fix typoLaurent Pinchart2022-07-271-1/+1
| | | | | | | | | | | Fix a typo in the mc-core.rst media driver API documentation. Due to its nature, the typo unfortunately caused a warning during documentation build. Fixes: 03b282861ca7 ("media: mc-entity: Add a new helper function to get a remote pad for a pad") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: mc-entity: Add a new helper function to get a remote pad for a padLaurent Pinchart2022-07-171-2/+3
| | | | | | | | | | | | | | | The newly added media_entity_remote_source_pad_unique() helper function handles use cases where the entity has a link enabled uniqueness constraint covering all pads. There are use cases where the constraint covers a specific pad only. Add a new media_pad_remote_pad_unique() function to handle this. It operates as media_entity_remote_source_pad_unique(), but on a given pad instead of on the entity. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: mc-entity: Add a new helper function to get a remote padLaurent Pinchart2022-07-171-1/+2
| | | | | | | | | | | | | | | | | | | | | The media_entity_remote_pad_first() helper function returns the first remote pad it finds connected to a given pad. Beside being possibly non-deterministic (as it stops at the first enabled link), the fact that it returns the first match makes it unsuitable for drivers that need to guarantee that a single link is enabled, for instance when an entity can process data from one of multiple sources at a time. For those use cases, add a new helper function, media_entity_remote_pad_unique(), that operates on an entity and returns a remote pad, with a guarantee that only one link is enabled. To ease its use in drivers, also add an inline wrapper that locates source pads specifically. A wrapper that locates sink pads can easily be added when needed. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: mc-entity: Rename media_entity_remote_pad() to ↵Laurent Pinchart2022-07-171-2/+1
| | | | | | | | | | | | | media_pad_remote_pad_first() The media_entity_remote_pad() is misnamed, as it operates on a pad and not an entity. Rename it to media_pad_remote_pad_first() to clarify its behaviour. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* media: Documentation: mc: Add media_device_{init,cleanup}Sakari Ailus2022-05-171-3/+10
| | | | | | | | | Document that drivers must first initialise a media device before registering it, and clean up once the media device is unregistered. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
* docs: get rid of :c:type explicit declarations for structsMauro Carvalho Chehab2020-10-151-12/+12
| | | | | | | | | | | | | | | | | | | | | The :c:type:`foo` only works properly with structs before Sphinx 3.x. On Sphinx 3.x, structs should now be declared using the .. c:struct, and referenced via :c:struct tag. As we now have the automarkup.py macro, that automatically convert: struct foo into cross-references, let's get rid of that, solving several warnings when building docs with Sphinx 3.x. Reviewed-by: André Almeida <andrealmeid@collabora.com> # blk-mq.rst Reviewed-by: Takashi Iwai <tiwai@suse.de> # sound Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
* media: docs: kAPI docs: move them to driver-apiMauro Carvalho Chehab2020-04-141-0/+309
All those documents describe the media driver API. So, move them to the right place within the Kernel documentation. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>