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// SPDX-License-Identifier: GPL-2.0+
/*
* vimc-streamer.c Virtual Media Controller Driver
*
* Copyright (C) 2018 Lucas A. M. Magalhães <lucmaga@gmail.com>
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include "vimc-streamer.h"
/**
* vimc_get_source_entity - get the entity connected with the first sink pad
*
* @ent: reference media_entity
*
* Helper function that returns the media entity containing the source pad
* linked with the first sink pad from the given media entity pad list.
*
* Return: The source pad or NULL, if it wasn't found.
*/
static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
{
struct media_pad *pad;
int i;
for (i = 0; i < ent->num_pads; i++) {
if (ent->pads[i].flags & MEDIA_PAD_FL_SOURCE)
continue;
pad = media_entity_remote_pad(&ent->pads[i]);
return pad ? pad->entity : NULL;
}
return NULL;
}
/**
* vimc_streamer_pipeline_terminate - Disable stream in all ved in stream
*
* @stream: the pointer to the stream structure with the pipeline to be
* disabled.
*
* Calls s_stream to disable the stream in each entity of the pipeline
*
*/
static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
{
struct vimc_ent_device *ved;
struct v4l2_subdev *sd;
while (stream->pipe_size) {
stream->pipe_size--;
ved = stream->ved_pipeline[stream->pipe_size];
ved->stream = NULL;
stream->ved_pipeline[stream->pipe_size] = NULL;
if (!is_media_entity_v4l2_subdev(ved->ent))
continue;
sd = media_entity_to_v4l2_subdev(ved->ent);
v4l2_subdev_call(sd, video, s_stream, 0);
}
}
/**
* vimc_streamer_pipeline_init - Initializes the stream structure
*
* @stream: the pointer to the stream structure to be initialized
* @ved: the pointer to the vimc entity initializing the stream
*
* Initializes the stream structure. Walks through the entity graph to
* construct the pipeline used later on the streamer thread.
* Calls vimc_streamer_s_stream() to enable stream in all entities of
* the pipeline.
*
* Return: 0 if success, error code otherwise.
*/
static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
struct vimc_ent_device *ved)
{
struct media_entity *entity;
struct video_device *vdev;
struct v4l2_subdev *sd;
int ret = 0;
stream->pipe_size = 0;
while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
if (!ved) {
vimc_streamer_pipeline_terminate(stream);
return -EINVAL;
}
stream->ved_pipeline[stream->pipe_size++] = ved;
ved->stream = stream;
if (is_media_entity_v4l2_subdev(ved->ent)) {
sd = media_entity_to_v4l2_subdev(ved->ent);
ret = v4l2_subdev_call(sd, video, s_stream, 1);
if (ret && ret != -ENOIOCTLCMD) {
pr_err("subdev_call error %s\n",
ved->ent->name);
vimc_streamer_pipeline_terminate(stream);
return ret;
}
}
entity = vimc_get_source_entity(ved->ent);
/* Check if the end of the pipeline was reached*/
if (!entity)
return 0;
/* Get the next device in the pipeline */
if (is_media_entity_v4l2_subdev(entity)) {
sd = media_entity_to_v4l2_subdev(entity);
ved = v4l2_get_subdevdata(sd);
} else {
vdev = container_of(entity,
struct video_device,
entity);
ved = video_get_drvdata(vdev);
}
}
vimc_streamer_pipeline_terminate(stream);
return -EINVAL;
}
/**
* vimc_streamer_thread - Process frames through the pipeline
*
* @data: vimc_stream struct of the current stream
*
* From the source to the sink, gets a frame from each subdevice and send to
* the next one of the pipeline at a fixed framerate.
*
* Return:
* Always zero (created as ``int`` instead of ``void`` to comply with
* kthread API).
*/
static int vimc_streamer_thread(void *data)
{
struct vimc_stream *stream = data;
u8 *frame = NULL;
int i;
set_freezable();
for (;;) {
try_to_freeze();
if (kthread_should_stop())
break;
for (i = stream->pipe_size - 1; i >= 0; i--) {
frame = stream->ved_pipeline[i]->process_frame(
stream->ved_pipeline[i], frame);
if (!frame || IS_ERR(frame))
break;
}
//wait for 60hz
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(HZ / 60);
}
return 0;
}
/**
* vimc_streamer_s_stream - Start/stop the streaming on the media pipeline
*
* @stream: the pointer to the stream structure of the current stream
* @ved: pointer to the vimc entity of the entity of the stream
* @enable: flag to determine if stream should start/stop
*
* When starting, check if there is no ``stream->kthread`` allocated. This
* should indicate that a stream is already running. Then, it initializes the
* pipeline, creates and runs a kthread to consume buffers through the pipeline.
* When stopping, analogously check if there is a stream running, stop the
* thread and terminates the pipeline.
*
* Return: 0 if success, error code otherwise.
*/
int vimc_streamer_s_stream(struct vimc_stream *stream,
struct vimc_ent_device *ved,
int enable)
{
int ret;
if (!stream || !ved)
return -EINVAL;
if (enable) {
if (stream->kthread)
return 0;
ret = vimc_streamer_pipeline_init(stream, ved);
if (ret)
return ret;
stream->kthread = kthread_run(vimc_streamer_thread, stream,
"vimc-streamer thread");
if (IS_ERR(stream->kthread))
return PTR_ERR(stream->kthread);
} else {
if (!stream->kthread)
return 0;
ret = kthread_stop(stream->kthread);
if (ret)
return ret;
stream->kthread = NULL;
vimc_streamer_pipeline_terminate(stream);
}
return 0;
}
EXPORT_SYMBOL_GPL(vimc_streamer_s_stream);
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