tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * vimc-streamer.c Virtual Media Controller Driver
4 *
5 * Copyright (C) 2018 Lucas A. M. Magalhães <lucmaga@gmail.com>
6 *
7 */
8
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/freezer.h>
12#include <linux/kthread.h>
13
14#include "vimc-streamer.h"
15
16/**
17 * vimc_get_source_entity - get the entity connected with the first sink pad
18 *
19 * @ent: reference media_entity
20 *
21 * Helper function that returns the media entity containing the source pad
22 * linked with the first sink pad from the given media entity pad list.
23 */
24static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
25{
26 struct media_pad *pad;
27 int i;
28
29 for (i = 0; i < ent->num_pads; i++) {
30 if (ent->pads[i].flags & MEDIA_PAD_FL_SOURCE)
31 continue;
32 pad = media_entity_remote_pad(&ent->pads[i]);
33 return pad ? pad->entity : NULL;
34 }
35 return NULL;
36}
37
38/*
39 * vimc_streamer_pipeline_terminate - Disable stream in all ved in stream
40 *
41 * @stream: the pointer to the stream structure with the pipeline to be
42 * disabled.
43 *
44 * Calls s_stream to disable the stream in each entity of the pipeline
45 *
46 */
47static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
48{
49 struct vimc_ent_device *ved;
50 struct v4l2_subdev *sd;
51
52 while (stream->pipe_size) {
53 stream->pipe_size--;
54 ved = stream->ved_pipeline[stream->pipe_size];
55 ved->stream = NULL;
56 stream->ved_pipeline[stream->pipe_size] = NULL;
57
58 if (!is_media_entity_v4l2_subdev(ved->ent))
59 continue;
60
61 sd = media_entity_to_v4l2_subdev(ved->ent);
62 v4l2_subdev_call(sd, video, s_stream, 0);
63 }
64}
65
66/*
67 * vimc_streamer_pipeline_init - initializes the stream structure
68 *
69 * @stream: the pointer to the stream structure to be initialized
70 * @ved: the pointer to the vimc entity initializing the stream
71 *
72 * Initializes the stream structure. Walks through the entity graph to
73 * construct the pipeline used later on the streamer thread.
74 * Calls s_stream to enable stream in all entities of the pipeline.
75 */
76static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
77 struct vimc_ent_device *ved)
78{
79 struct media_entity *entity;
80 struct video_device *vdev;
81 struct v4l2_subdev *sd;
82 int ret = 0;
83
84 stream->pipe_size = 0;
85 while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) {
86 if (!ved) {
87 vimc_streamer_pipeline_terminate(stream);
88 return -EINVAL;
89 }
90 stream->ved_pipeline[stream->pipe_size++] = ved;
91 ved->stream = stream;
92
93 if (is_media_entity_v4l2_subdev(ved->ent)) {
94 sd = media_entity_to_v4l2_subdev(ved->ent);
95 ret = v4l2_subdev_call(sd, video, s_stream, 1);
96 if (ret && ret != -ENOIOCTLCMD) {
97 pr_err("subdev_call error %s\n",
98 ved->ent->name);
99 vimc_streamer_pipeline_terminate(stream);
100 return ret;
101 }
102 }
103
104 entity = vimc_get_source_entity(ved->ent);
105 /* Check if the end of the pipeline was reached*/
106 if (!entity)
107 return 0;
108
109 /* Get the next device in the pipeline */
110 if (is_media_entity_v4l2_subdev(entity)) {
111 sd = media_entity_to_v4l2_subdev(entity);
112 ved = v4l2_get_subdevdata(sd);
113 } else {
114 vdev = container_of(entity,
115 struct video_device,
116 entity);
117 ved = video_get_drvdata(vdev);
118 }
119 }
120
121 vimc_streamer_pipeline_terminate(stream);
122 return -EINVAL;
123}
124
125static int vimc_streamer_thread(void *data)
126{
127 struct vimc_stream *stream = data;
128 u8 *frame = NULL;
129 int i;
130
131 set_freezable();
132
133 for (;;) {
134 try_to_freeze();
135 if (kthread_should_stop())
136 break;
137
138 for (i = stream->pipe_size - 1; i >= 0; i--) {
139 frame = stream->ved_pipeline[i]->process_frame(
140 stream->ved_pipeline[i], frame);
141 if (!frame || IS_ERR(frame))
142 break;
143 }
144 //wait for 60hz
145 set_current_state(TASK_UNINTERRUPTIBLE);
146 schedule_timeout(HZ / 60);
147 }
148
149 return 0;
150}
151
152int vimc_streamer_s_stream(struct vimc_stream *stream,
153 struct vimc_ent_device *ved,
154 int enable)
155{
156 int ret;
157
158 if (!stream || !ved)
159 return -EINVAL;
160
161 if (enable) {
162 if (stream->kthread)
163 return 0;
164
165 ret = vimc_streamer_pipeline_init(stream, ved);
166 if (ret)
167 return ret;
168
169 stream->kthread = kthread_run(vimc_streamer_thread, stream,
170 "vimc-streamer thread");
171
172 if (IS_ERR(stream->kthread))
173 return PTR_ERR(stream->kthread);
174
175 } else {
176 if (!stream->kthread)
177 return 0;
178
179 ret = kthread_stop(stream->kthread);
180 if (ret)
181 return ret;
182
183 stream->kthread = NULL;
184
185 vimc_streamer_pipeline_terminate(stream);
186 }
187
188 return 0;
189}
190EXPORT_SYMBOL_GPL(vimc_streamer_s_stream);
191
192MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC) Streamer");
193MODULE_AUTHOR("Lucas A. M. Magalhães <lucmaga@gmail.com>");
194MODULE_LICENSE("GPL");