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linux-next/drivers/media/v4l2-core/v4l2-mc.c
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

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Media Controller ancillary functions
*
* Copyright (c) 2016 Mauro Carvalho Chehab <mchehab@kernel.org>
* Copyright (C) 2016 Shuah Khan <shuahkh@osg.samsung.com>
* Copyright (C) 2006-2010 Nokia Corporation
* Copyright (c) 2016 Intel Corporation.
*/
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/usb.h>
#include <media/media-device.h>
#include <media/media-entity.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-mc.h>
#include <media/v4l2-subdev.h>
#include <media/videobuf2-core.h>
int v4l2_mc_create_media_graph(struct media_device *mdev)
{
struct media_entity *entity;
struct media_entity *if_vid = NULL, *if_aud = NULL;
struct media_entity *tuner = NULL, *decoder = NULL;
struct media_entity *io_v4l = NULL, *io_vbi = NULL, *io_swradio = NULL;
bool is_webcam = false;
u32 flags;
int ret, pad_sink, pad_source;
if (!mdev)
return 0;
media_device_for_each_entity(entity, mdev) {
switch (entity->function) {
case MEDIA_ENT_F_IF_VID_DECODER:
if_vid = entity;
break;
case MEDIA_ENT_F_IF_AUD_DECODER:
if_aud = entity;
break;
case MEDIA_ENT_F_TUNER:
tuner = entity;
break;
case MEDIA_ENT_F_ATV_DECODER:
decoder = entity;
break;
case MEDIA_ENT_F_IO_V4L:
io_v4l = entity;
break;
case MEDIA_ENT_F_IO_VBI:
io_vbi = entity;
break;
case MEDIA_ENT_F_IO_SWRADIO:
io_swradio = entity;
break;
case MEDIA_ENT_F_CAM_SENSOR:
is_webcam = true;
break;
}
}
/* It should have at least one I/O entity */
if (!io_v4l && !io_vbi && !io_swradio) {
dev_warn(mdev->dev, "Didn't find any I/O entity\n");
return -EINVAL;
}
/*
* Here, 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 not enough
* for mc-centric hardware, it is enough for v4l2 interface centric
* PC-consumer's hardware.
*/
if (is_webcam) {
if (!io_v4l) {
dev_warn(mdev->dev, "Didn't find a MEDIA_ENT_F_IO_V4L\n");
return -EINVAL;
}
media_device_for_each_entity(entity, mdev) {
if (entity->function != MEDIA_ENT_F_CAM_SENSOR)
continue;
ret = media_create_pad_link(entity, 0,
io_v4l, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "Failed to create a sensor link\n");
return ret;
}
}
if (!decoder)
return 0;
}
/* The device isn't a webcam. So, it should have a decoder */
if (!decoder) {
dev_warn(mdev->dev, "Decoder not found\n");
return -EINVAL;
}
/* Link the tuner and IF video output pads */
if (tuner) {
if (if_vid) {
pad_source = media_get_pad_index(tuner, false,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(if_vid, true,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "Couldn't get tuner and/or PLL pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
if_vid, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "Couldn't create tuner->PLL link)\n");
return ret;
}
pad_source = media_get_pad_index(if_vid, false,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(decoder, true,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "get decoder and/or PLL pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(if_vid, pad_source,
decoder, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link PLL to decoder\n");
return ret;
}
} else {
pad_source = media_get_pad_index(tuner, false,
PAD_SIGNAL_ANALOG);
pad_sink = media_get_pad_index(decoder, true,
PAD_SIGNAL_ANALOG);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner and/or decoder pad(s): (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
decoder, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret)
return ret;
}
if (if_aud) {
pad_source = media_get_pad_index(tuner, false,
PAD_SIGNAL_AUDIO);
pad_sink = media_get_pad_index(if_aud, true,
PAD_SIGNAL_AUDIO);
if (pad_source < 0 || pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner and/or decoder pad(s) for audio: (%d, %d)\n",
pad_source, pad_sink);
return -EINVAL;
}
ret = media_create_pad_link(tuner, pad_source,
if_aud, pad_sink,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link tuner->audio PLL\n");
return ret;
}
} else {
if_aud = tuner;
}
}
/* Create demod to V4L, VBI and SDR radio links */
if (io_v4l) {
pad_source = media_get_pad_index(decoder, false, PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for V4L I/O\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_v4l, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to V4L I/O\n");
return ret;
}
}
if (io_swradio) {
pad_source = media_get_pad_index(decoder, false, PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for SDR\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_swradio, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to SDR\n");
return ret;
}
}
if (io_vbi) {
pad_source = media_get_pad_index(decoder, false, PAD_SIGNAL_DV);
if (pad_source < 0) {
dev_warn(mdev->dev, "couldn't get decoder output pad for VBI\n");
return -EINVAL;
}
ret = media_create_pad_link(decoder, pad_source,
io_vbi, 0,
MEDIA_LNK_FL_ENABLED);
if (ret) {
dev_warn(mdev->dev, "couldn't link decoder output to VBI\n");
return ret;
}
}
/* Create links for the media connectors */
flags = MEDIA_LNK_FL_ENABLED;
media_device_for_each_entity(entity, mdev) {
switch (entity->function) {
case MEDIA_ENT_F_CONN_RF:
if (!tuner)
continue;
pad_sink = media_get_pad_index(tuner, true,
PAD_SIGNAL_ANALOG);
if (pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner analog pad sink\n");
return -EINVAL;
}
ret = media_create_pad_link(entity, 0, tuner,
pad_sink,
flags);
break;
case MEDIA_ENT_F_CONN_SVIDEO:
case MEDIA_ENT_F_CONN_COMPOSITE:
pad_sink = media_get_pad_index(decoder, true,
PAD_SIGNAL_ANALOG);
if (pad_sink < 0) {
dev_warn(mdev->dev, "couldn't get tuner analog pad sink\n");
return -EINVAL;
}
ret = media_create_pad_link(entity, 0, decoder,
pad_sink,
flags);
break;
default:
continue;
}
if (ret)
return ret;
flags = 0;
}
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_mc_create_media_graph);
int v4l_enable_media_source(struct video_device *vdev)
{
struct media_device *mdev = vdev->entity.graph_obj.mdev;
int ret = 0, err;
if (!mdev)
return 0;
mutex_lock(&mdev->graph_mutex);
if (!mdev->enable_source)
goto end;
err = mdev->enable_source(&vdev->entity, &vdev->pipe);
if (err)
ret = -EBUSY;
end:
mutex_unlock(&mdev->graph_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(v4l_enable_media_source);
void v4l_disable_media_source(struct video_device *vdev)
{
struct media_device *mdev = vdev->entity.graph_obj.mdev;
if (mdev) {
mutex_lock(&mdev->graph_mutex);
if (mdev->disable_source)
mdev->disable_source(&vdev->entity);
mutex_unlock(&mdev->graph_mutex);
}
}
EXPORT_SYMBOL_GPL(v4l_disable_media_source);
int v4l_vb2q_enable_media_source(struct vb2_queue *q)
{
struct v4l2_fh *fh = q->owner;
if (fh && fh->vdev)
return v4l_enable_media_source(fh->vdev);
return 0;
}
EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
/* -----------------------------------------------------------------------------
* Pipeline power management
*
* Entities must be powered up when part of a pipeline that contains at least
* one open video device node.
*
* To achieve this use the entity use_count field to track the number of users.
* For entities corresponding to video device nodes the use_count field stores
* the users count of the node. For entities corresponding to subdevs the
* use_count field stores the total number of users of all video device nodes
* in the pipeline.
*
* The v4l2_pipeline_pm_{get, put}() functions must be called in the open() and
* close() handlers of video device nodes. It increments or decrements the use
* count of all subdev entities in the pipeline.
*
* To react to link management on powered pipelines, the link setup notification
* callback updates the use count of all entities in the source and sink sides
* of the link.
*/
/*
* pipeline_pm_use_count - Count the number of users of a pipeline
* @entity: The entity
*
* Return the total number of users of all video device nodes in the pipeline.
*/
static int pipeline_pm_use_count(struct media_entity *entity,
struct media_graph *graph)
{
int use = 0;
media_graph_walk_start(graph, entity);
while ((entity = media_graph_walk_next(graph))) {
if (is_media_entity_v4l2_video_device(entity))
use += entity->use_count;
}
return use;
}
/*
* pipeline_pm_power_one - Apply power change to an entity
* @entity: The entity
* @change: Use count change
*
* Change the entity use count by @change. If the entity is a subdev update its
* power state by calling the core::s_power operation when the use count goes
* from 0 to != 0 or from != 0 to 0.
*
* Return 0 on success or a negative error code on failure.
*/
static int pipeline_pm_power_one(struct media_entity *entity, int change)
{
struct v4l2_subdev *subdev;
int ret;
subdev = is_media_entity_v4l2_subdev(entity)
? media_entity_to_v4l2_subdev(entity) : NULL;
if (entity->use_count == 0 && change > 0 && subdev != NULL) {
ret = v4l2_subdev_call(subdev, core, s_power, 1);
if (ret < 0 && ret != -ENOIOCTLCMD)
return ret;
}
entity->use_count += change;
WARN_ON(entity->use_count < 0);
if (entity->use_count == 0 && change < 0 && subdev != NULL)
v4l2_subdev_call(subdev, core, s_power, 0);
return 0;
}
/*
* pipeline_pm_power - Apply power change to all entities in a pipeline
* @entity: The entity
* @change: Use count change
*
* Walk the pipeline to update the use count and the power state of all non-node
* entities.
*
* Return 0 on success or a negative error code on failure.
*/
static int pipeline_pm_power(struct media_entity *entity, int change,
struct media_graph *graph)
{
struct media_entity *first = entity;
int ret = 0;
if (!change)
return 0;
media_graph_walk_start(graph, entity);
while (!ret && (entity = media_graph_walk_next(graph)))
if (is_media_entity_v4l2_subdev(entity))
ret = pipeline_pm_power_one(entity, change);
if (!ret)
return ret;
media_graph_walk_start(graph, first);
while ((first = media_graph_walk_next(graph))
&& first != entity)
if (is_media_entity_v4l2_subdev(first))
pipeline_pm_power_one(first, -change);
return ret;
}
static int v4l2_pipeline_pm_use(struct media_entity *entity, unsigned int use)
{
struct media_device *mdev = entity->graph_obj.mdev;
int change = use ? 1 : -1;
int ret;
mutex_lock(&mdev->graph_mutex);
/* Apply use count to node. */
entity->use_count += change;
WARN_ON(entity->use_count < 0);
/* Apply power change to connected non-nodes. */
ret = pipeline_pm_power(entity, change, &mdev->pm_count_walk);
if (ret < 0)
entity->use_count -= change;
mutex_unlock(&mdev->graph_mutex);
return ret;
}
int v4l2_pipeline_pm_get(struct media_entity *entity)
{
return v4l2_pipeline_pm_use(entity, 1);
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_get);
void v4l2_pipeline_pm_put(struct media_entity *entity)
{
/* Powering off entities shouldn't fail. */
WARN_ON(v4l2_pipeline_pm_use(entity, 0));
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_put);
int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
unsigned int notification)
{
struct media_graph *graph = &link->graph_obj.mdev->pm_count_walk;
struct media_entity *source = link->source->entity;
struct media_entity *sink = link->sink->entity;
int source_use;
int sink_use;
int ret = 0;
source_use = pipeline_pm_use_count(source, graph);
sink_use = pipeline_pm_use_count(sink, graph);
if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH &&
!(flags & MEDIA_LNK_FL_ENABLED)) {
/* Powering off entities is assumed to never fail. */
pipeline_pm_power(source, -sink_use, graph);
pipeline_pm_power(sink, -source_use, graph);
return 0;
}
if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
(flags & MEDIA_LNK_FL_ENABLED)) {
ret = pipeline_pm_power(source, sink_use, graph);
if (ret < 0)
return ret;
ret = pipeline_pm_power(sink, source_use, graph);
if (ret < 0)
pipeline_pm_power(source, -sink_use, graph);
}
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_pipeline_link_notify);
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