[PATCH v6 4/4] media: stm32-dcmi: add support of several sub-devices

From: Hugues Fruchet
Date: Wed Aug 14 2019 - 09:49:23 EST


Add support of several sub-devices within pipeline instead
of a single one.
This allows to support a CSI-2 camera sensor connected
through a CSI-2 to parallel bridge.

Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx>
---
drivers/media/platform/stm32/stm32-dcmi.c | 217 +++++++++++++++++++++++++++---
1 file changed, 198 insertions(+), 19 deletions(-)

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
index 302c40e..b6ef229 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -172,6 +172,7 @@ struct stm32_dcmi {

struct media_device mdev;
struct media_pad vid_cap_pad;
+ struct media_pipeline pipeline;
};

static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier *n)
@@ -583,6 +584,144 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
spin_unlock_irq(&dcmi->irqlock);
}

+static struct media_entity *dcmi_find_source(struct stm32_dcmi *dcmi)
+{
+ struct media_entity *entity = &dcmi->vdev->entity;
+ struct media_pad *pad;
+
+ /* Walk searching for entity having no sink */
+ while (1) {
+ pad = &entity->pads[0];
+ if (!(pad->flags & MEDIA_PAD_FL_SINK))
+ break;
+
+ pad = media_entity_remote_pad(pad);
+ if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
+ break;
+
+ entity = pad->entity;
+ }
+
+ return entity;
+}
+
+static int dcmi_pipeline_s_fmt(struct stm32_dcmi *dcmi,
+ struct v4l2_subdev_pad_config *pad_cfg,
+ struct v4l2_subdev_format *format)
+{
+ struct media_entity *entity = &dcmi->entity.source->entity;
+ struct v4l2_subdev *subdev;
+ struct media_pad *sink_pad = NULL;
+ struct media_pad *src_pad = NULL;
+ struct media_pad *pad = NULL;
+ struct v4l2_subdev_format fmt = *format;
+ bool found = false;
+ int ret;
+
+ /*
+ * Starting from sensor subdevice, walk within
+ * pipeline and set format on each subdevice
+ */
+ while (1) {
+ unsigned int i;
+
+ /* Search if current entity has a source pad */
+ for (i = 0; i < entity->num_pads; i++) {
+ pad = &entity->pads[i];
+ if (pad->flags & MEDIA_PAD_FL_SOURCE) {
+ src_pad = pad;
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ break;
+
+ subdev = media_entity_to_v4l2_subdev(entity);
+
+ /* Propagate format on sink pad if any, otherwise source pad */
+ if (sink_pad)
+ pad = sink_pad;
+
+ dev_dbg(dcmi->dev, "\"%s\":%d pad format set to 0x%x %ux%u\n",
+ subdev->name, pad->index, format->format.code,
+ format->format.width, format->format.height);
+
+ fmt.pad = pad->index;
+ ret = v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
+ if (ret < 0) {
+ dev_err(dcmi->dev, "%s: Failed to set format 0x%x %ux%u on \"%s\":%d pad (%d)\n",
+ __func__, format->format.code,
+ format->format.width, format->format.height,
+ subdev->name, pad->index, ret);
+ return ret;
+ }
+
+ if (fmt.format.code != format->format.code ||
+ fmt.format.width != format->format.width ||
+ fmt.format.height != format->format.height) {
+ dev_dbg(dcmi->dev, "\"%s\":%d pad format has been changed to 0x%x %ux%u\n",
+ subdev->name, pad->index, fmt.format.code,
+ fmt.format.width, fmt.format.height);
+ }
+
+ /* Walk to next entity */
+ sink_pad = media_entity_remote_pad(src_pad);
+ if (!sink_pad || !is_media_entity_v4l2_subdev(sink_pad->entity))
+ break;
+
+ entity = sink_pad->entity;
+ }
+ *format = fmt;
+
+ return 0;
+}
+
+static int dcmi_pipeline_s_stream(struct stm32_dcmi *dcmi, int state)
+{
+ struct media_entity *entity = &dcmi->vdev->entity;
+ struct v4l2_subdev *subdev;
+ struct media_pad *pad;
+ int ret;
+
+ /* Start/stop all entities within pipeline */
+ while (1) {
+ pad = &entity->pads[0];
+ if (!(pad->flags & MEDIA_PAD_FL_SINK))
+ break;
+
+ pad = media_entity_remote_pad(pad);
+ if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
+ break;
+
+ entity = pad->entity;
+ subdev = media_entity_to_v4l2_subdev(entity);
+
+ ret = v4l2_subdev_call(subdev, video, s_stream, state);
+ if (ret < 0 && ret != -ENOIOCTLCMD) {
+ dev_err(dcmi->dev, "%s: \"%s\" failed to %s streaming (%d)\n",
+ __func__, subdev->name,
+ state ? "start" : "stop", ret);
+ return ret;
+ }
+
+ dev_dbg(dcmi->dev, "\"%s\" is %s\n",
+ subdev->name, state ? "started" : "stopped");
+ }
+
+ return 0;
+}
+
+static int dcmi_pipeline_start(struct stm32_dcmi *dcmi)
+{
+ return dcmi_pipeline_s_stream(dcmi, 1);
+}
+
+static void dcmi_pipeline_stop(struct stm32_dcmi *dcmi)
+{
+ dcmi_pipeline_s_stream(dcmi, 0);
+}
+
static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
{
struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
@@ -597,14 +736,17 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
goto err_release_buffers;
}

- /* Enable stream on the sub device */
- ret = v4l2_subdev_call(dcmi->entity.source, video, s_stream, 1);
- if (ret && ret != -ENOIOCTLCMD) {
- dev_err(dcmi->dev, "%s: Failed to start streaming, subdev streamon error",
- __func__);
+ ret = media_pipeline_start(&dcmi->vdev->entity, &dcmi->pipeline);
+ if (ret < 0) {
+ dev_err(dcmi->dev, "%s: Failed to start streaming, media pipeline start error (%d)\n",
+ __func__, ret);
goto err_pm_put;
}

+ ret = dcmi_pipeline_start(dcmi);
+ if (ret)
+ goto err_media_pipeline_stop;
+
spin_lock_irq(&dcmi->irqlock);

/* Set bus width */
@@ -676,7 +818,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
if (ret) {
dev_err(dcmi->dev, "%s: Start streaming failed, cannot start capture\n",
__func__);
- goto err_subdev_streamoff;
+ goto err_pipeline_stop;
}

/* Enable interruptions */
@@ -687,8 +829,11 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)

return 0;

-err_subdev_streamoff:
- v4l2_subdev_call(dcmi->entity.source, video, s_stream, 0);
+err_pipeline_stop:
+ dcmi_pipeline_stop(dcmi);
+
+err_media_pipeline_stop:
+ media_pipeline_stop(&dcmi->vdev->entity);

err_pm_put:
pm_runtime_put(dcmi->dev);
@@ -713,13 +858,10 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
{
struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
struct dcmi_buf *buf, *node;
- int ret;

- /* Disable stream on the sub device */
- ret = v4l2_subdev_call(dcmi->entity.source, video, s_stream, 0);
- if (ret && ret != -ENOIOCTLCMD)
- dev_err(dcmi->dev, "%s: Failed to stop streaming, subdev streamoff error (%d)\n",
- __func__, ret);
+ dcmi_pipeline_stop(dcmi);
+
+ media_pipeline_stop(&dcmi->vdev->entity);

spin_lock_irq(&dcmi->irqlock);

@@ -937,8 +1079,7 @@ static int dcmi_set_fmt(struct stm32_dcmi *dcmi, struct v4l2_format *f)
mf->width = sd_framesize.width;
mf->height = sd_framesize.height;

- ret = v4l2_subdev_call(dcmi->entity.source, pad,
- set_fmt, NULL, &format);
+ ret = dcmi_pipeline_s_fmt(dcmi, NULL, &format);
if (ret < 0)
return ret;

@@ -1412,6 +1553,12 @@ static int dcmi_set_default_fmt(struct stm32_dcmi *dcmi)
return 0;
}

+/*
+ * FIXME: For the time being we only support subdevices
+ * which expose RGB & YUV "parallel form" mbus code (_2X8).
+ * Nevertheless, this allows to support serial source subdevices
+ * and serial to parallel bridges which conform to this.
+ */
static const struct dcmi_format dcmi_formats[] = {
{
.fourcc = V4L2_PIX_FMT_RGB565,
@@ -1537,7 +1684,20 @@ static int dcmi_graph_notify_complete(struct v4l2_async_notifier *notifier)
struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
int ret;

+ /*
+ * Now that the graph is complete,
+ * we search for the source subdevice
+ * in order to expose it through V4L2 interface
+ */
+ dcmi->entity.source =
+ media_entity_to_v4l2_subdev(dcmi_find_source(dcmi));
+ if (!dcmi->entity.source) {
+ dev_err(dcmi->dev, "Source subdevice not found\n");
+ return -ENODEV;
+ }
+
dcmi->vdev->ctrl_handler = dcmi->entity.source->ctrl_handler;
+
ret = dcmi_formats_init(dcmi);
if (ret) {
dev_err(dcmi->dev, "No supported mediabus format found\n");
@@ -1582,12 +1742,31 @@ static int dcmi_graph_notify_bound(struct v4l2_async_notifier *notifier,
struct v4l2_async_subdev *asd)
{
struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
+ unsigned int ret;
+ int src_pad;

- dev_dbg(dcmi->dev, "Subdev %s bound\n", subdev->name);
+ dev_dbg(dcmi->dev, "Subdev \"%s\" bound\n", subdev->name);

- dcmi->entity.source = subdev;
+ /*
+ * Link this sub-device to DCMI, it could be
+ * a parallel camera sensor or a bridge
+ */
+ src_pad = media_entity_get_fwnode_pad(&subdev->entity,
+ subdev->fwnode,
+ MEDIA_PAD_FL_SOURCE);
+
+ ret = media_create_pad_link(&subdev->entity, src_pad,
+ &dcmi->vdev->entity, 0,
+ MEDIA_LNK_FL_IMMUTABLE |
+ MEDIA_LNK_FL_ENABLED);
+ if (ret)
+ dev_err(dcmi->dev, "Failed to create media pad link with subdev \"%s\"\n",
+ subdev->name);
+ else
+ dev_dbg(dcmi->dev, "DCMI is now linked to \"%s\"\n",
+ subdev->name);

- return 0;
+ return ret;
}

static const struct v4l2_async_notifier_operations dcmi_graph_notify_ops = {
--
2.7.4