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Message-Id: <20200415013044.1778572-3-helen.koike@collabora.com>
Date: Tue, 14 Apr 2020 22:30:42 -0300
From: Helen Koike <helen.koike@...labora.com>
To: linux-media@...r.kernel.org
Cc: kernel@...labora.com, linux-kernel@...r.kernel.org,
linux-rockchip@...ts.infradead.org, hans.verkuil@...co.com,
skhan@...uxfoundation.org, niklas.soderlund@...natech.se,
mchehab@...nel.org, Helen Koike <helen.koike@...labora.com>
Subject: [PATCH v3 2/4] media: v4l2-common: add helper functions to call s_stream() callbacks
Add v4l2_pipeline_stream_{enable,disable} helper functions to iterate
through the subdevices in a given stream (i.e following links from sink
to source) and call .s_stream() callback.
Add stream_count on the subdevice object for simultaneous streaming from
different video devices which shares subdevices.
Prevent calling .s_stream(true) if it was already called previously by
another stream.
Prevent calling .s_stream(false) from one stream when there are still
others active.
If .s_stream(true) fails, call .s_stream(false) in the reverse order.
Signed-off-by: Helen Koike <helen.koike@...labora.com>
---
Changes in v3:
- re-write helpers to use media walkers as in v1, but with
v4l2_pipeline_subdevs_get() to reverse the order we call s_stream(true)
in subdevices.
- rename size to max_size (and update docs) in v4l2_pipeline_subdevs_get() to
reflect the meaning of the argument.
- add if defined(CONFIG_MEDIA_CONTROLLER) around helpers
Changes in v2:
- re-write helpers to not use media walkers
drivers/media/v4l2-core/v4l2-common.c | 125 ++++++++++++++++++++++++++
include/media/v4l2-common.h | 43 +++++++++
include/media/v4l2-subdev.h | 2 +
3 files changed, 170 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index 9e8eb45a5b03c..2f991a1a57d7c 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -442,3 +442,128 @@ int v4l2_fill_pixfmt(struct v4l2_pix_format *pixfmt, u32 pixelformat,
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fill_pixfmt);
+
+#if defined(CONFIG_MEDIA_CONTROLLER)
+
+/*
+ * v4l2_pipeline_subdevs_get - Assemble a list of subdevices in a pipeline
+ * @subdevs: the array to be filled.
+ * @max_size: max number of elements that can fit in subdevs array.
+ *
+ * Walk from a video node, following links from sink to source and fill the
+ * array with subdevices in the path.
+ * The walker performs a depth-first traversal, which means that, in a topology
+ * sd1->sd2->sd3->vdev, sd1 will be the first element placed in the array.
+ *
+ * Return the number of subdevices filled in the array.
+ */
+static int v4l2_pipeline_subdevs_get(struct video_device *vdev,
+ struct media_pipeline *pipe,
+ struct v4l2_subdev **subdevs,
+ unsigned int max_size)
+{
+ struct media_entity *entity = &vdev->entity;
+ struct media_device *mdev = entity->graph_obj.mdev;
+ int idx = 0;
+ int ret;
+
+ mutex_lock(&mdev->graph_mutex);
+
+ if (!pipe->streaming_count) {
+ ret = media_graph_walk_init(&pipe->graph, mdev);
+ if (ret) {
+ mutex_unlock(&mdev->graph_mutex);
+ return ret;
+ }
+ }
+
+ media_graph_walk_start(&pipe->graph, entity);
+
+ while ((entity = media_graph_walk_next_stream(&pipe->graph))) {
+ if (!is_media_entity_v4l2_subdev(entity))
+ continue;
+ if (WARN_ON(idx >= max_size)) {
+ mutex_unlock(&mdev->graph_mutex);
+ return -EINVAL;
+ }
+ subdevs[idx++] = media_entity_to_v4l2_subdev(entity);
+ }
+
+ if (!pipe->streaming_count)
+ media_graph_walk_cleanup(&pipe->graph);
+
+ mutex_unlock(&mdev->graph_mutex);
+
+ return idx;
+}
+
+__must_check int v4l2_pipeline_stream_enable(struct video_device *vdev,
+ struct media_pipeline *pipe)
+{
+ struct media_device *mdev = vdev->entity.graph_obj.mdev;
+ struct v4l2_subdev *subdevs[MEDIA_ENTITY_ENUM_MAX_DEPTH];
+ struct v4l2_subdev *sd;
+ int i, size, ret;
+
+ size = v4l2_pipeline_subdevs_get(vdev, pipe,
+ subdevs, ARRAY_SIZE(subdevs));
+ if (size <= 0)
+ return size;
+
+ /* Call s_stream() in reverse order to enable sensors last */
+ for (i = size - 1; i >= 0; i--) {
+ sd = subdevs[i];
+ if (sd->stream_count++)
+ continue;
+ dev_dbg(mdev->dev,
+ "enabling stream for '%s'\n", sd->entity.name);
+ ret = v4l2_subdev_call(sd, video, s_stream, true);
+ if (ret && ret != -ENOIOCTLCMD) {
+ sd->stream_count = 0;
+ goto err_stream_disable;
+ }
+ }
+
+ return 0;
+
+err_stream_disable:
+ for (i++; i < size; i++) {
+ sd = subdevs[i];
+ if (--sd->stream_count)
+ continue;
+ dev_dbg(mdev->dev,
+ "disabling stream for '%s'\n", sd->entity.name);
+ v4l2_subdev_call(sd, video, s_stream, false);
+ };
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_pipeline_stream_enable);
+
+void v4l2_pipeline_stream_disable(struct video_device *vdev,
+ struct media_pipeline *pipe)
+{
+ struct media_device *mdev = vdev->entity.graph_obj.mdev;
+ struct v4l2_subdev *subdevs[MEDIA_ENTITY_ENUM_MAX_DEPTH];
+ unsigned int i;
+ int size;
+
+ size = v4l2_pipeline_subdevs_get(vdev, pipe,
+ subdevs, ARRAY_SIZE(subdevs));
+ if (WARN_ON(size < 0))
+ return;
+
+ /* Call s_stream() in order to disable sensors first */
+ for (i = 0; i < size; i++) {
+ struct v4l2_subdev *sd = subdevs[i];
+
+ if (--sd->stream_count)
+ continue;
+ dev_dbg(mdev->dev,
+ "disabling stream for '%s'\n", sd->entity.name);
+ v4l2_subdev_call(sd, video, s_stream, false);
+ }
+}
+EXPORT_SYMBOL_GPL(v4l2_pipeline_stream_disable);
+
+#endif /* CONFIG_MEDIA_CONTROLLER */
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 150ee16ebd811..dc46812120cdc 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -539,4 +539,47 @@ static inline void v4l2_buffer_set_timestamp(struct v4l2_buffer *buf,
buf->timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
}
+#if defined(CONFIG_MEDIA_CONTROLLER)
+
+/**
+ * v4l2_pipeline_stream_enable - Call .s_stream(true) callbacks in the stream
+ * @vdev: Starting video device.
+ * @pipe: Pipeline this entity belongs to.
+ *
+ * Call .s_stream(true) callback in all the subdevices participating in the
+ * stream, i.e. following links from sink to source.
+ *
+ * .s_stream(true) is also called from sink to source, i.e. in a topology
+ * sd1->sd2->sd3->vdev, .s_stream(true) of sd3 is called first.
+ *
+ * Calls to this function can be nested, in which case the same number of
+ * v4l2_pipeline_stream_disable() calls will be required to disable streaming
+ * through subdevices in the pipeline.
+ * The pipeline pointer must be identical for all nested calls to
+ * v4l2_pipeline_stream_enable().
+ */
+__must_check int v4l2_pipeline_stream_enable(struct video_device *vdev,
+ struct media_pipeline *pipe);
+
+/**
+ * v4l2_pipeline_stream_disable - Call .s_stream(false) callbacks in the stream
+ * @vdev: Starting video device.
+ * @pipe: Pipeline this entity belongs to.
+ *
+ * Call .s_stream(false) callback in all the subdevices participating in the
+ * stream, i.e. following links from sink to source.
+ *
+ * s_stream(false) is called in a reverse order from
+ * v4l2_pipeline_stream_enable(), i.e. in a topology sd1->sd2->sd3->vdev,
+ * .s_stream(false) of sd1 is called first.
+ *
+ * If multiple calls to v4l2_pipeline_stream_enable() have been made, the same
+ * number of calls to this function are required to disable streaming through
+ * subdevices in the pipeline.
+ */
+void v4l2_pipeline_stream_disable(struct video_device *vdev,
+ struct media_pipeline *pipe);
+
+#endif /* CONFIG_MEDIA_CONTROLLER */
+
#endif /* V4L2_COMMON_H_ */
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a4848de598521..20f913a9f70c5 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -838,6 +838,7 @@ struct v4l2_subdev_platform_data {
* @subdev_notifier: A sub-device notifier implicitly registered for the sub-
* device using v4l2_device_register_sensor_subdev().
* @pdata: common part of subdevice platform data
+ * @stream_count: Stream count for the subdevice.
*
* Each instance of a subdev driver should create this struct, either
* stand-alone or embedded in a larger struct.
@@ -869,6 +870,7 @@ struct v4l2_subdev {
struct v4l2_async_notifier *notifier;
struct v4l2_async_notifier *subdev_notifier;
struct v4l2_subdev_platform_data *pdata;
+ unsigned int stream_count;
};
--
2.26.0
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