media: mc: Expand MUST_CONNECT flag to always require an enabled link

The MEDIA_PAD_FL_MUST_CONNECT flag indicates that the pad requires an
enabled link to stream, but only if it has any link at all. This makes
little sense, as if a pad is part of a pipeline, there are very few use
cases for an active link to be mandatory only if links exist at all. A
review of in-tree drivers confirms they all need an enabled link for
pads marked with the MEDIA_PAD_FL_MUST_CONNECT flag.

Expand the scope of the flag by rejecting pads that have no links at
all. This requires modifying the pipeline build code to add those pads
to the pipeline.

Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Rename pad variable to clarify intent

The pad local variable in the media_pipeline_explore_next_link()
function is used to store the pad through which the entity has been
reached. Rename it to origin to reflect that and make the code easier to
read. This will be even more important in subsequent commits when
expanding the function with additional logic.

Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Add num_links flag to media_pad

Maintain a counter of the links connected to a pad in the media_pad
structure. This helps checking if a pad is connected to anything, which
will be used in the pipeline building code.

Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Fix flags handling when creating pad links

The media_create_pad_link() function doesn't correctly clear reject link
type flags, nor does it set the DATA_LINK flag. It only works because
the MEDIA_LNK_FL_DATA_LINK flag's value is 0.

Fix it by returning an error if any link type flag is set. This doesn't
introduce any regression, as nobody calls the media_create_pad_link()
function with link type flags (easily checked by grepping for the flag
in the source code, there are very few hits).

Set the MEDIA_LNK_FL_DATA_LINK explicitly, which is a no-op that the
compiler will optimize out, but is still useful to make the code more
explicit and easier to understand.

Cc: stable@vger.kernel.org # 6.1
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Add local pad to pipeline regardless of the link state

When building pipelines by following links, the
media_pipeline_explore_next_link() function only traverses enabled
links. The remote pad of a disabled link is not added to the pipeline,
and neither is the local pad. While the former is correct as disabled
links should not be followed, not adding the local pad breaks processing
of the MEDIA_PAD_FL_MUST_CONNECT flag.

The MEDIA_PAD_FL_MUST_CONNECT flag is checked in the
__media_pipeline_start() function that iterates over all pads after
populating the pipeline. If the pad is not present, the check gets
skipped, rendering it useless.

Fix this by adding the local pad of all links regardless of their state,
only skipping the remote pad for disabled links.

Cc: stable@vger.kernel.org # 6.1
Fixes: ae219872834a ("media: mc: entity: Rewrite media_pipeline_start()")
Reported-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Closes: https://lore.kernel.org/linux-media/7658a15a-80c5-219f-2477-2a94ba6c6ba1@kontron.de
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Check pad flag validity

Check the validity of pad flags on entity init. Exactly one of the flags
must be set.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Make media_get_pad_index() use pad type flag

Use the pad flag specifying the pad type instead of a boolean in
preparation for internal source pads.

Also make the loop variable unsigned.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: Make media_entity_get_fwnode_pad() fwnode argument const

fwnode_graph_parse_endpoint() fwnode argument is now const, therefore make
media_entity_get_fwnode_pad() fwnode argument const as well.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc: entity: Fix minor issues in comments and documentation

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: Get media_device directly from pad

Various functions access the media_device from a pad by going through
the entity the pad belongs to. Remove the level of indirection and get
the media_device from the pad directly.

Fixes: 9e3576a1ae2b ("media: mc: convert pipeline funcs to take media_pad")
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: Add entity iterator for media_pipeline

Add a media_pipeline_for_each_entity() macro to iterate over entities in
a pipeline. This should be used by driver as a replacement of the
media_graph_walk API, as iterating over the media_pipeline uses the
cached list of pads and is thus more efficient.

Deprecate the media_graph_walk API to indicate it shouldn't be used in
new drivers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: mc: entity: Add pad iterator for media_pipeline

Add a media_pipeline_for_each_pad() macro to iterate over pads in a
pipeline. This should be used by driver as a replacement of the
media_graph_walk API, as iterating over the media_pipeline uses the
cached list of pads and is thus more efficient.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: mc: entity: Fix doc for media_graph_walk_init

There is no media_graph_walk_free(). media_graph_walk_cleanup() is used
to release the resources.

Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: mc: Improve the media_entity_has_pad_interdep() documentation

Document the function parameters, the requirements on the pad0 and pad1
arguments, the locking requirements and the return value. Also improve
the documentation of the corresponding .has_pad_interdep() operation,
stating clearly that the operation must be called through the
media_entity_has_pad_interdep() function only.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: mc: convert pipeline funcs to take media_pad

Now that the pipeline is stored into pads instead of entities, we can
change the relevant functions to take pads instead of entities.

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: mc: entity: Add has_pad_interdep entity operation

Add a new media entity operation, has_pad_interdep. The optional op is
used to discover the pad interdependencies inside an entity during the
pipeline construction.

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: mc: entity: Rewrite media_pipeline_start()

[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: mc: entity: add alloc variant of pipeline_start

Add new variant of media_pipeline_start(), media_pipeline_alloc_start().

media_pipeline_alloc_start() can be used by drivers that do not need to
extend the media_pipeline. The function will either use the pipeline
already associated with the entity, if such exists, or allocate a new
pipeline.

When media_pipeline_stop() is called and the pipeline's use count drops
to zero, the pipeline is automatically freed.

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: mc: entity: Add media_entity_pipeline() to access the media pipeline

Replace direct access to the pipe field in drivers with a new helper
function. This will allow easier refactoring of media pipeline handling
in the MC core behind the scenes without affecting drivers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@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: mc: entity: Move media_entity_get_fwnode_pad() out of graph walk section

The media_entity_get_fwnode_pad() function is unrelated to the graph
traversal code that it is currently bundled with. Move it with the
media_entity_remote_pad() function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@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: mc: entity: Merge media_entity_enum_init and __media_entity_enum_init

The media_entity_enum_init() function is a wrapper around
__media_entity_enum_init() that turns a media_device pointer argument
into the maximum entity ID in the corresponding media graph.
__media_entity_enum_init() is never used outside of
media_entity_enum_init(), so the two functions can be merged together.

Signed-off-by: Laurent Pinchart <laurent.pinchart@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: mc: entity: Add iterator helper for entity pads

Add an iterator helper to easily cycle through all pads in an entity and
use it in media-entity and media-device code where appropriate.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@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: mc: entity: Rename streaming_count -> start_count

'streaming_count' is a bit misleading name, as the count is increased
with media_pipeline_start(). Let's rename it to 'start_count' instead.

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: mc-entity: Add a new helper function to get a remote pad for a pad

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 pad

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 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: entity: Use dedicated data link iterator

Where iteration over links for an entity is clearly assuming that
all of those links are data links, use the new iterator to guarantee
that assumption is met.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: entity: Add iterator for entity data links

Iterating over the links for an entity is a somewhat common need
through the media subsystem, but generally the assumption is that
they will all be data links. To meet that assumption add a new macro
that iterates through an entity's links and skips non-data links.

Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: entity: Add support for ancillary links

Add functions to create ancillary links, so that they don't need to
be manually created by users.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: entity: Add link_type_name() helper

Now we have three types of media link, printing the right name during
debug output is slightly more complicated. Add a helper function to
make it easier.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: entity: Skip non-data links in graph iteration

When iterating over the media graph, don't follow links that are not
data links.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: entity: skip non-data link when removing reverse links

The original implementation removes reverse links for any input link and
assumes the presense of sink/source.
It fails when the link is a not a data link.
media_entity_remove_links when there's an ancillary link can also fail.

We only need to remove reverse links for a data link.

Signed-off-by: Yunke Cao <yunkec@google.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: media-entity: Simplify media_pipeline_start()

The media_pipeline_start() function has two purposes: it constructs a
pipeline by recording the entities that are part of it, gathered from a
graph walk, and validate the media links. The pipeline pointer is stored
in the media_entity structure as part of this process, and the entity's
stream count is increased, to record that the entity is streaming.

When multiple video nodes are present in a pipeline,
media_pipeline_start() is typically called on all of them, with the same
pipeline pointer. This is taken into account in media_pipeline_start()
by skipping validation for entities that are already part of the
pipeline, while returning an error if an entity is part of a different
pipeline.

It turns out that this process is overly complicated. When
media_pipeline_start() is called for the first time, it constructs the
full pipeline, adding all entities and validating all the links.
Subsequent calls to media_pipeline_start() are then nearly no-ops, they
only increase the stream count on the pipeline and on all entities.

The media_entity stream_count field is used for two purposes: checking
if the entity is streaming, and detecting when a call to
media_pipeline_stop() balances needs to reset the entity pipe pointer to
NULL. The former can easily be replaced by a check of the pipe pointer.

Simplify media_pipeline_start() by avoiding the pipeline walk on all
calls but the first one, and drop the media_entity stream_count field.
media_pipeline_stop() is updated accordingly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Sakari Ailus: Drop redundant '!= NULL' as discussed]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

media: media-entity: Add media_pad_is_streaming() helper function

Add a function to test if a pad is part of a pipeline currently
streaming, and use it through drivers to replace direct access to the
stream_count field. This will help reworking pipeline start/stop without
disturbing drivers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

media: mc: mc-entity.c: Use bitmap_zalloc() when applicable

'ent_enum->bmap' is a bitmap. So use 'bitmap_zalloc()' to simplify
code, improve the semantic and avoid some open-coded arithmetic in
allocator arguments.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

While at it, remove a useless 'bitmap_zero()'.

Link: https://lore.kernel.org/linux-media/b11f646dda189f490c06bf671f64a2cc0af4d45c.1638397089.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: mc: drop an unused debug function

The gobj_type() function translates the media object type into
a name, being useful for debugging purposes. It is currently
not used. So, drop it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: mc: mc-entity.c: Fix typo

s/entity in the other end/entity at the other end/

[hverkuil: also remove the spurious space after 'link']

Signed-off-by: Sebastian Fricke <sebastian.fricke@posteo.net>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: entity: Add lockdep check to media graph walk

It was always assumed that walking the media graph would require holding
the media_device graph_mutex but this was not documented nor checked for.

Add a lockdep check to graph walk init and iter, and document the need for
acquiring the graph_mutex.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: entity: Pass entity to get_fwnode_pad operation

Add a missing pointer to the entity in the media_entity operation
get_fwnode_pad. There are no implementers of this op yet, but a future
entity that does so will almost certainly need a reference to itself
to carry out the work.

operation")

Fixes: ae45cd5efc120 ("[media] media: entity: Add get_fwnode_pad entity
Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: mc-entity.c: use WARN_ON, validate link pads

Use WARN_ON instead of BUG_ON.

Add two new WARN_ONs to verify that the source pad is really a source
and that the sink pad is really a sink.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: use ! instead of == NULL for source and sink]
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: mc-entity.c: use & to check pad flags, not ==

These are bits so to test if a pad is a sink you use & but not ==.

It looks like the only reason this hasn't caused problems before is that
media_get_pad_index() is currently only used with pads that do not set the
MEDIA_PAD_FL_MUST_CONNECT flag. So a pad really had only the SINK or SOURCE
flag set and nothing else.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org> # for v5.3 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: move drivers/media/media-* to drivers/media/mc/mc-*

It is really weird that the media controller sources are all top-level
in drivers/media. It is a bit of a left-over from long ago when most
media sources were all at the top-level. At some point we reorganized
the directory structure, but the media-*.c sources where never moved
to their own directory.

So create a new mc directory and move all sources there. Also rename
the prefix from media- to mc-.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>