media: v4l2-event: Annotate struct v4l2_subscribed_event with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for
struct v4l2_subscribed_event.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: lijian <lijian@yulong.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: v4l2-dev/event: add v4l2_event_wake_all()

When unregistering a V4L2 device node, make sure any filehandles
that are waiting for an event are woken up.

Add v4l2_event_wake_all() to v4l2-event.c and call it from
video_unregister_device().

Otherwise userspace might never know that a device node was removed.

[hverkuil: checkpatch: replaced 'if (vdev == NULL)' by 'if (!vdev)']

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

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 655 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: v4l2-event: keep track of the timestamp in ns

Internally use ktime_get_ns() to get the timestamp of the event.
Only convert to timespec when interfacing with userspace.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: fix usage of whitespaces and on indentation

On several places, whitespaces are being used for indentation,
or even at the end of the line.

Fix them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: v4l2-event.rst: improve events description

Both v4l2-event.rst and v4l2-event.h have an overview of
events, but there are some inconsistencies there:

- at v4l2-event, the event's ring buffer is called kevent. Its
name is, instead, v4l2_kevent;

- Some things are mentioned on both places (with different words),
others are either on one of the files.

In order to cleanup this mess, put everything at v4l2-event.rst
and improve it to be a little more coherent and to have cross
references.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] media: Drop FSF's postal address from the source code files

Drop the FSF's postal address from the source code files that typically
contain mostly the license text. Of the 628 removed instances, 578 are
outdated.

The patch has been created with the following command without manual edits:

git grep -l "675 Mass Ave\|59 Temple Place\|51 Franklin St" -- \
drivers/media/ include/media|while read i; do i=$i perl -e '
open(F,"< $ENV{i}");
$a=join("", <F>);
$a =~ s/[ \t]*\*\n.*You should.*\n.*along with.*\n.*(\n.*USA.*$)?\n//m
&& $a =~ s/(^.*)Or, (point your browser to) /$1To obtain the license, $2\n$1/m;
close(F);
open(F, "> $ENV{i}");
print F $a;
close(F);'; done

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

[media] get rid of a number of problems at the cross references

As warned by linuxdoc[1] tool, using:

$ for i in $(git grep kernel-doc Documentation/media/kapi/|cut -d: -f4); do kernel-lintdoc --sloppy $i; done

include/media/v4l2-dev.h:118 :WARN: function name from comment differs: v4l2_prio_close <--> v4l2_prio_check
include/media/v4l2-mc.h:56 [kernel-doc WARN] : enum name from comment differs: if_vid_dec_index <--> if_vid_dec_pad_index
include/media/v4l2-mc.h:71 [kernel-doc WARN] : enum name from comment differs: if_aud_dec_index <--> if_aud_dec_pad_index
include/media/v4l2-mem2mem.h:396 [kernel-doc WARN] : function name from comment differs: v4l2_m2m_num_src_bufs_ready <--> v4l2_m2m_num_dst_bufs_ready
drivers/media/dvb-core/dvb_math.h:28 [kernel-doc WARN] : function name from comment differs: cintlog2 <--> intlog2
include/media/v4l2-subdev.h:215 [kernel-doc WARN] : struct name from comment differs: s_radio <--> v4l2_subdev_tuner_ops
include/media/v4l2-subdev.h:890 [kernel-doc WARN] : function name from comment differs: v4l2_set_subdevdata <--> v4l2_set_subdev_hostdata
include/media/v4l2-subdev.h:901 [kernel-doc WARN] : function name from comment differs: v4l2_get_subdevdata <--> v4l2_get_subdev_hostdata
drivers/media/dvb-core/dvb_ringbuffer.h:196 [kernel-doc WARN] : function name from comment differs: dvb_ringbuffer_writeuser <--> dvb_ringbuffer_write_user
include/media/videobuf2-core.h:399 [kernel-doc WARN] : struct name from comment differs: vb2_ops <--> vb2_buf_ops
include/media/media-entity.h:132 [kernel-doc ERROR] : duplicate parameter definition 'source'
include/media/media-entity.h:477 [kernel-doc WARN] : function name from comment differs: media_entity_enum_test <--> media_entity_enum_test_and_set
include/media/media-entity.h:535 [kernel-doc WARN] : function name from comment differs: gobj_to_entity <--> gobj_to_pad
include/media/media-entity.h:544 [kernel-doc WARN] : function name from comment differs: gobj_to_entity <--> gobj_to_link
include/media/media-entity.h:553 [kernel-doc WARN] : function name from comment differs: gobj_to_entity <--> gobj_to_intf
include/media/media-entity.h:562 [kernel-doc WARN] : function name from comment differs: gobj_to_entity <--> intf_to_devnode
include/media/rc-core.h:234 [kernel-doc WARN] : function name from comment differs: rc_open <--> rc_close
include/media/v4l2-ctrls.h:397 [kernel-doc WARN] : missing initial short description of 'v4l2_ctrl_handler_init'
include/media/v4l2-dev.h:118 [kernel-doc WARN] : function name from comment differs: v4l2_prio_close <--> v4l2_prio_check
include/media/v4l2-event.h:225 [kernel-doc WARN] : missing initial short description of 'v4l2_src_change_event_subscribe'

[1] https://return42.github.io/linuxdoc/linux.html

The above are real issues at the documentation. On several cases,
caused by cut-and-paste.

Fix them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] v4l2-event.h: document all functions

Several functions weren't documented. Document them all.

While here, makes checkpatch.pl happy.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] v4l2-event.h: fix comments and add to DocBook

The comments there are good enough for DocBook, however they're
using a wrong format. Fix and add to device-drivers.xml.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>

[media] v4l: Add source change event

This event indicates that the video device has encountered
a source parameter change during runtime. This can typically be a
resolution change detected by a video decoder OR a format change
detected by an input connector.

This needs to be nofified to the userspace and the application may
be expected to reallocate buffers before proceeding. The application
can subscribe to events on a specific pad or input port which
it is interested in.

Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

[media] V4L: Add v4l2_event_subdev_unsubscribe() helper function

Add a v4l2 core helper function that can be used as the subdev
.unsubscribe_event handler. This allows to eliminate some
boilerplate from drivers that are only handling the control events.

Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l, smiapp, smiapp-pll, adp1653: Update contact information

Update contact information to correspond my e-mail address changes.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2: make vidioc_(un)subscribe_event const

Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_(un)subscribe_event.
Adding const for write-only ioctls was decided during the 2012 Media Workshop.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-event: fix regression with initial event handling

If the V4L2_EVENT_SUB_FL_SEND_INITIAL was set, then the application expects
to receive an initial event of the initial value of the control.

However, commit c53c2549333b340e2662dc64ec81323476b69a97 that added the new
v4l2_subscribed_event_ops introduced a regression: while the code still queued
that initial event the __v4l2_event_queue_fh() function was modified to ignore
such requests if sev->elems was 0 (meaning that the event subscription wasn't
finished yet).

And sev->elems was only set to a non-zero value after the add operation
returned.

This patch fixes this by passing the elems value to the add function. Then the
add function can set it before queuing the initial event.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-event: Add v4l2_subscribed_event_ops

Just like with ctrl events, drivers may want to get called back on
listener add / remove for other event types too. Rather then special
casing all of this in subscribe / unsubscribe event it is better to
use ops for this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-event.h: add overview documentation to the header

It's getting confusing who is linking to what, so add an overview at
the start of the header.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-ctrls/v4l2-events: small coding style cleanups

Thanks to Laurent Pinchart <laurent.pinchart@ideasonboard.com>.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-event: add optional merge and replace callbacks

When the event queue for a subscribed event is full, then the oldest
event is dropped. It would be nice if the contents of that oldest
event could be merged with the next-oldest. That way no information is
lost, only intermediate steps are lost.

This patch adds optional replace() (called when only one kevent was allocated)
and merge() (called when more than one kevent was allocated) callbacks that
will be called to do this job.

These two callbacks are implemented for the V4L2_EVENT_CTRL event.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-event/ctrls/fh: allocate events per fh and per type instead of just per-fh

The driver had to decide how many events to allocate when the v4l2_fh struct
was created. It was possible to add more events afterwards, but there was no
way to ensure that you wouldn't miss important events if the event queue
would fill up for that filehandle.

In addition, once there were no more free events, any new events were simply
dropped on the floor.

For the control event in particular this made life very difficult since
control status/value changes could just be missed if the number of allocated
events and the speed at which the application read events was too low to keep
up with the number of generated events. The application would have no idea
what the latest state was for a control since it could have missed the latest
control change.

So this patch makes some major changes in how events are allocated. Instead
of allocating events per-filehandle they are now allocated when subscribing an
event. So for that particular event type N events (determined by the driver)
are allocated. Those events are reserved for that particular event type.
This ensures that you will not miss events for a particular type altogether.

In addition, if there are N events in use and a new event is raised, then
the oldest event is dropped and the new one is added. So the latest event
is always available.

This can be further improved by adding the ability to merge the state of
two events together, ensuring that no data is lost at all. This will be
added in the next patch.

This also makes it possible to allow the user to determine the number of
events that will be allocated. This is not implemented at the moment, but
would be trivial.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-ctrls/event: remove struct v4l2_ctrl_fh, instead use v4l2_subscribed_event

The v4l2_ctrl_fh struct connected v4l2_ctrl with v4l2_fh so the control
would know which filehandles subscribed to it. However, it is much easier
to use struct v4l2_subscribed_event directly for that and get rid of that
intermediate struct.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-events/fh: merge v4l2_events into v4l2_fh

Drivers that supported events used to be rare, but now that controls can also
raise events this will become much more common since almost all drivers have
controls.

This means that keeping struct v4l2_events as a separate struct make no more
sense. Merging it into struct v4l2_fh simplifies things substantially as it
is now an integral part of the filehandle struct.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

[media] v4l2-ctrls: add control events

Whenever a control changes value or state an event is sent to anyone
that subscribed to it.

This functionality is useful for control panels but also for applications
that need to wait for (usually status) controls to change value.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

V4L/DVB: V4L: Events: Add backend

Add event handling backend to V4L2. The backend handles event subscription
and delivery to file handles. Event subscriptions are based on file handle.
Events may be delivered to all subscribed file handles on a device
independent of where they originate from.

Signed-off-by: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>