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/freezer.h> 11 #include <linux/kthread.h> 12 13 #include "vimc-streamer.h" 14 15 /** 16 * vimc_get_source_entity - get the entity connected with the first sink pad 17 * 18 * @ent: reference media_entity 19 * 20 * Helper function that returns the media entity containing the source pad 21 * linked with the first sink pad from the given media entity pad list. 22 * 23 * Return: The source pad or NULL, if it wasn't found. 24 */ 25 static struct media_entity *vimc_get_source_entity(struct media_entity *ent) 26 { 27 struct media_pad *pad; 28 int i; 29 30 for (i = 0; i < ent->num_pads; i++) { 31 if (ent->pads[i].flags & MEDIA_PAD_FL_SOURCE) 32 continue; 33 pad = media_entity_remote_pad(&ent->pads[i]); 34 return pad ? pad->entity : NULL; 35 } 36 return NULL; 37 } 38 39 /** 40 * vimc_streamer_pipeline_terminate - Disable stream in all ved in stream 41 * 42 * @stream: the pointer to the stream structure with the pipeline to be 43 * disabled. 44 * 45 * Calls s_stream to disable the stream in each entity of the pipeline 46 * 47 */ 48 static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream) 49 { 50 struct vimc_ent_device *ved; 51 struct v4l2_subdev *sd; 52 53 while (stream->pipe_size) { 54 stream->pipe_size--; 55 ved = stream->ved_pipeline[stream->pipe_size]; 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 vimc_streamer_s_stream() to enable stream in all entities of 75 * the pipeline. 76 * 77 * Return: 0 if success, error code otherwise. 78 */ 79 static int vimc_streamer_pipeline_init(struct vimc_stream *stream, 80 struct vimc_ent_device *ved) 81 { 82 struct media_entity *entity; 83 struct video_device *vdev; 84 struct v4l2_subdev *sd; 85 int ret = 0; 86 87 stream->pipe_size = 0; 88 while (stream->pipe_size < VIMC_STREAMER_PIPELINE_MAX_SIZE) { 89 if (!ved) { 90 vimc_streamer_pipeline_terminate(stream); 91 return -EINVAL; 92 } 93 stream->ved_pipeline[stream->pipe_size++] = ved; 94 95 if (is_media_entity_v4l2_subdev(ved->ent)) { 96 sd = media_entity_to_v4l2_subdev(ved->ent); 97 ret = v4l2_subdev_call(sd, video, s_stream, 1); 98 if (ret && ret != -ENOIOCTLCMD) { 99 dev_err(ved->dev, "subdev_call error %s\n", 100 ved->ent->name); 101 vimc_streamer_pipeline_terminate(stream); 102 return ret; 103 } 104 } 105 106 entity = vimc_get_source_entity(ved->ent); 107 /* Check if the end of the pipeline was reached */ 108 if (!entity) { 109 /* the first entity of the pipe should be source only */ 110 if (!vimc_is_source(ved->ent)) { 111 dev_err(ved->dev, 112 "first entity in the pipe '%s' is not a source\n", 113 ved->ent->name); 114 vimc_streamer_pipeline_terminate(stream); 115 return -EPIPE; 116 } 117 return 0; 118 } 119 120 /* Get the next device in the pipeline */ 121 if (is_media_entity_v4l2_subdev(entity)) { 122 sd = media_entity_to_v4l2_subdev(entity); 123 ved = v4l2_get_subdevdata(sd); 124 } else { 125 vdev = container_of(entity, 126 struct video_device, 127 entity); 128 ved = video_get_drvdata(vdev); 129 } 130 } 131 132 vimc_streamer_pipeline_terminate(stream); 133 return -EINVAL; 134 } 135 136 /** 137 * vimc_streamer_thread - Process frames through the pipeline 138 * 139 * @data: vimc_stream struct of the current stream 140 * 141 * From the source to the sink, gets a frame from each subdevice and send to 142 * the next one of the pipeline at a fixed framerate. 143 * 144 * Return: 145 * Always zero (created as ``int`` instead of ``void`` to comply with 146 * kthread API). 147 */ 148 static int vimc_streamer_thread(void *data) 149 { 150 struct vimc_stream *stream = data; 151 u8 *frame = NULL; 152 int i; 153 154 set_freezable(); 155 156 for (;;) { 157 try_to_freeze(); 158 if (kthread_should_stop()) 159 break; 160 161 for (i = stream->pipe_size - 1; i >= 0; i--) { 162 frame = stream->ved_pipeline[i]->process_frame( 163 stream->ved_pipeline[i], frame); 164 if (!frame || IS_ERR(frame)) 165 break; 166 } 167 //wait for 60hz 168 set_current_state(TASK_UNINTERRUPTIBLE); 169 schedule_timeout(HZ / 60); 170 } 171 172 return 0; 173 } 174 175 /** 176 * vimc_streamer_s_stream - Start/stop the streaming on the media pipeline 177 * 178 * @stream: the pointer to the stream structure of the current stream 179 * @ved: pointer to the vimc entity of the entity of the stream 180 * @enable: flag to determine if stream should start/stop 181 * 182 * When starting, check if there is no ``stream->kthread`` allocated. This 183 * should indicate that a stream is already running. Then, it initializes the 184 * pipeline, creates and runs a kthread to consume buffers through the pipeline. 185 * When stopping, analogously check if there is a stream running, stop the 186 * thread and terminates the pipeline. 187 * 188 * Return: 0 if success, error code otherwise. 189 */ 190 int vimc_streamer_s_stream(struct vimc_stream *stream, 191 struct vimc_ent_device *ved, 192 int enable) 193 { 194 int ret; 195 196 if (!stream || !ved) 197 return -EINVAL; 198 199 if (enable) { 200 if (stream->kthread) 201 return 0; 202 203 ret = vimc_streamer_pipeline_init(stream, ved); 204 if (ret) 205 return ret; 206 207 stream->kthread = kthread_run(vimc_streamer_thread, stream, 208 "vimc-streamer thread"); 209 210 if (IS_ERR(stream->kthread)) { 211 ret = PTR_ERR(stream->kthread); 212 dev_err(ved->dev, "kthread_run failed with %d\n", ret); 213 vimc_streamer_pipeline_terminate(stream); 214 stream->kthread = NULL; 215 return ret; 216 } 217 218 } else { 219 if (!stream->kthread) 220 return 0; 221 222 ret = kthread_stop(stream->kthread); 223 /* 224 * kthread_stop returns -EINTR in cases when streamon was 225 * immediately followed by streamoff, and the thread didn't had 226 * a chance to run. Ignore errors to stop the stream in the 227 * pipeline. 228 */ 229 if (ret) 230 dev_dbg(ved->dev, "kthread_stop returned '%d'\n", ret); 231 232 stream->kthread = NULL; 233 234 vimc_streamer_pipeline_terminate(stream); 235 } 236 237 return 0; 238 } 239