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