kernel_optimize_test/include/media/v4l2-mc.h
Ezequiel Garcia 8fd390b89c media: Split v4l2_pipeline_pm_use into v4l2_pipeline_pm_{get, put}
Currently, v4l2_pipeline_pm_use() prototype is:

  int v4l2_pipeline_pm_use(struct media_entity *entity, int use)

Where the 'use' argument shall only be set to '1' for enable/power-on,
or to '0' for disable/power-off. The integer return is specified
as only meaningful when 'use' is set to '1'.

Let's enforce this semantic by splitting the function in two:
v4l2_pipeline_pm_get and v4l2_pipeline_pm_put. This is done
for several reasons.

It makes the API easier to use (or harder to misuse).
It removes the constraint on the values the 'use' argument
shall take. Also, it removes the need to constraint
the return value, by making v4l2_pipeline_pm_put void return.

And last, it's more consistent with other kernel APIs, such
as the runtime pm APIs, which makes the code more symmetric.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
2020-03-02 15:11:40 +01:00

170 lines
5.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* v4l2-mc.h - Media Controller V4L2 types and prototypes
*
* Copyright (C) 2016 Mauro Carvalho Chehab <mchehab@kernel.org>
* Copyright (C) 2006-2010 Nokia Corporation
* Copyright (c) 2016 Intel Corporation.
*/
#ifndef _V4L2_MC_H
#define _V4L2_MC_H
#include <media/media-device.h>
#include <media/v4l2-dev.h>
#include <linux/types.h>
/* We don't need to include pci.h or usb.h here */
struct pci_dev;
struct usb_device;
#ifdef CONFIG_MEDIA_CONTROLLER
/**
* v4l2_mc_create_media_graph() - create Media Controller links at the graph.
*
* @mdev: pointer to the &media_device struct.
*
* Add links between the entities commonly found on PC customer's hardware at
* the V4L2 side: camera sensors, audio and video PLL-IF decoders, tuners,
* analog TV decoder and I/O entities (video, VBI and Software Defined Radio).
*
* .. note::
*
* Webcams are modelled on a very simple way: the sensor is
* connected directly to the I/O entity. All dirty details, like
* scaler and crop HW are hidden. While such mapping is enough for v4l2
* interface centric PC-consumer's hardware, V4L2 subdev centric camera
* hardware should not use this routine, as it will not build the right graph.
*/
int v4l2_mc_create_media_graph(struct media_device *mdev);
/**
* v4l_enable_media_source() - Hold media source for exclusive use
* if free
*
* @vdev: pointer to struct video_device
*
* This interface calls enable_source handler to determine if
* media source is free for use. The enable_source handler is
* responsible for checking is the media source is free and
* start a pipeline between the media source and the media
* entity associated with the video device. This interface
* should be called from v4l2-core and dvb-core interfaces
* that change the source configuration.
*
* Return: returns zero on success or a negative error code.
*/
int v4l_enable_media_source(struct video_device *vdev);
/**
* v4l_disable_media_source() - Release media source
*
* @vdev: pointer to struct video_device
*
* This interface calls disable_source handler to release
* the media source. The disable_source handler stops the
* active media pipeline between the media source and the
* media entity associated with the video device.
*
* Return: returns zero on success or a negative error code.
*/
void v4l_disable_media_source(struct video_device *vdev);
/*
* v4l_vb2q_enable_media_tuner - Hold media source for exclusive use
* if free.
* @q - pointer to struct vb2_queue
*
* Wrapper for v4l_enable_media_source(). This function should
* be called from v4l2-core to enable the media source with
* pointer to struct vb2_queue as the input argument. Some
* v4l2-core interfaces don't have access to video device and
* this interface finds the struct video_device for the q and
* calls v4l_enable_media_source().
*/
int v4l_vb2q_enable_media_source(struct vb2_queue *q);
/**
* v4l2_pipeline_pm_get - Increase the use count of a pipeline
* @entity: The root entity of a pipeline
*
* Update the use count of all entities in the pipeline and power entities on.
*
* This function is intended to be called in video node open. It uses
* struct media_entity.use_count to track the power status. The use
* of this function should be paired with v4l2_pipeline_link_notify().
*
* Return 0 on success or a negative error code on failure.
*/
int v4l2_pipeline_pm_get(struct media_entity *entity);
/**
* v4l2_pipeline_pm_put - Decrease the use count of a pipeline
* @entity: The root entity of a pipeline
*
* Update the use count of all entities in the pipeline and power entities off.
*
* This function is intended to be called in video node release. It uses
* struct media_entity.use_count to track the power status. The use
* of this function should be paired with v4l2_pipeline_link_notify().
*/
void v4l2_pipeline_pm_put(struct media_entity *entity);
/**
* v4l2_pipeline_link_notify - Link management notification callback
* @link: The link
* @flags: New link flags that will be applied
* @notification: The link's state change notification type (MEDIA_DEV_NOTIFY_*)
*
* React to link management on powered pipelines by updating the use count of
* all entities in the source and sink sides of the link. Entities are powered
* on or off accordingly. The use of this function should be paired
* with v4l2_pipeline_pm_{get,put}().
*
* Return 0 on success or a negative error code on failure. Powering entities
* off is assumed to never fail. This function will not fail for disconnection
* events.
*/
int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
unsigned int notification);
#else /* CONFIG_MEDIA_CONTROLLER */
static inline int v4l2_mc_create_media_graph(struct media_device *mdev)
{
return 0;
}
static inline int v4l_enable_media_source(struct video_device *vdev)
{
return 0;
}
static inline void v4l_disable_media_source(struct video_device *vdev)
{
}
static inline int v4l_vb2q_enable_media_source(struct vb2_queue *q)
{
return 0;
}
static inline int v4l2_pipeline_pm_get(struct media_entity *entity)
{
return 0;
}
static inline void v4l2_pipeline_pm_put(struct media_entity *entity)
{}
static inline int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
unsigned int notification)
{
return 0;
}
#endif /* CONFIG_MEDIA_CONTROLLER */
#endif /* _V4L2_MC_H */