Re: [PATCH v2 3/3] media: stm32-dcmi: add support of several sub-devices

From: Hugues FRUCHET
Date: Tue Jul 02 2019 - 11:27:35 EST

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Hi Sakari,

On 6/20/19 5:54 PM, Sakari Ailus wrote:
> Hi Hugues,
>
> Thank you for the update.
>
> On Tue, Jun 11, 2019 at 10:48:32AM +0200, Hugues Fruchet wrote:
>> 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 | 207 +++++++++++++++++++++++++++---
>> 1 file changed, 189 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c
>> index 3a69783..144912f 100644
>> --- a/drivers/media/platform/stm32/stm32-dcmi.c
>> +++ b/drivers/media/platform/stm32/stm32-dcmi.c
>> @@ -173,6 +173,7 @@ 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)
>> @@ -584,6 +585,135 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
>> spin_unlock_irq(&dcmi->irqlock);
>> }
>>
>> +static struct media_entity *dcmi_find_sensor(struct stm32_dcmi *dcmi)
>
> You generally should be only concerned with the next entity connected to the
> one you're in control of, not the rest of the pipeline.

This was discussed with Laurent here:
https://www.spinics.net/lists/linux-media/msg153417.html
and it's OK because DCMI is a video node and we are not
exposing media controller interface to userspace.

>
>> +{
>> + struct media_entity *entity = &dcmi->vdev->entity;
>> + struct v4l2_subdev *subdev;
>> + struct media_pad *pad;
>> +
>> + /* Walk searching for entity having no sink */
>> + while (1) {
>> + pad = &entity->pads[0];
>> +
>> + subdev = media_entity_to_v4l2_subdev(entity);
>> +
>> + 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->sensor->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);
>
> Generally speaking, on MC-centric devices, the user space needs to
> configure the pipeline. The driver's responsibility is to validate it
> (through the link_validate media entity and subdev pad ops). I.e. set_fmt
> is only used through the subdev nodes.
>
ditto

>> + if (ret < 0)
>> + return ret;
>> +
>> + /* 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);
>
> Please only call this on the next upstream sub-device. See e.g. the
> ipu3-cio2 or omap3isp driver for an example.
>
ditto

>> + 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);
>> @@ -598,14 +728,17 @@ 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->sensor, 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 */
>> @@ -677,7 +810,7 @@ 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 */
>> @@ -688,8 +821,11 @@ static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
>>
>> return 0;
>>
>> -err_subdev_streamoff:
>> - v4l2_subdev_call(dcmi->sensor, 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);
>> @@ -714,13 +850,10 @@ 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->sensor, 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);
>>
>> @@ -938,8 +1071,7 @@ 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->sensor, pad,
>> - set_fmt, NULL, &format);
>> + ret = dcmi_pipeline_s_fmt(dcmi, NULL, &format);
>> if (ret < 0)
>> return ret;
>>
>> @@ -1530,7 +1662,19 @@ 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 camera sensor subdevice
>> + * in order to expose it through V4L2 interface
>> + */
>> + dcmi->sensor = media_entity_to_v4l2_subdev(dcmi_find_sensor(dcmi));
>> + if (!dcmi->sensor) {
>> + dev_err(dcmi->dev, "No camera sensor subdevice found\n");
>> + return -ENODEV;
>> + }
>> +
>> dcmi->vdev->ctrl_handler = dcmi->sensor->ctrl_handler;
>> +
>> ret = dcmi_formats_init(dcmi);
>> if (ret) {
>> dev_err(dcmi->dev, "No supported mediabus format found\n");
>> @@ -1574,12 +1718,30 @@ 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);
>>
>> - dcmi->sensor = 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 = {
>> @@ -1639,6 +1801,15 @@ static int dcmi_graph_init(struct stm32_dcmi *dcmi)
>> return ret;
>> }
>>
>> + /* Register all the subdev nodes */
>> + ret = v4l2_device_register_subdev_nodes(&dcmi->v4l2_dev);
>> + if (ret) {
>> + dev_err(dcmi->dev, "Failed to register subdev nodes\n");
>> + v4l2_async_notifier_unregister(&dcmi->notifier);
>> + of_node_put(dcmi->entity.node);
>> + return ret;
>> + }
>> +
>> return 0;
>> }
>>
>

BR,
Hugues.

Next message: Liran Alon: "Re: [PATCH 2/3] KVM: nVMX: allow setting the VMFUNC controls MSR"
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