[PATCH 03/12] [media] vb2: add in-fence support to QBUF

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From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>

Receive in-fence from userspace and add support for waiting on them
before queueing the buffer to the driver. Buffers are only queued
to the driver once they are ready. A buffer is ready when its
in-fence signals.

v2:
	- fix vb2_queue_or_prepare_buf() ret check
	- remove check for VB2_MEMORY_DMABUF only (Javier)
	- check num of ready buffers to start streaming
	- when queueing, start from the first ready buffer
	- handle queue cancel

Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
---
 drivers/media/Kconfig                    |  1 +
 drivers/media/v4l2-core/videobuf2-core.c | 97 +++++++++++++++++++++++++-------
 drivers/media/v4l2-core/videobuf2-v4l2.c | 15 ++++-
 include/media/videobuf2-core.h           |  7 ++-
 4 files changed, 99 insertions(+), 21 deletions(-)

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
index 55d9c2b..3cd1d3d 100644
--- a/drivers/media/Kconfig
+++ b/drivers/media/Kconfig
@@ -11,6 +11,7 @@ config CEC_NOTIFIER
 menuconfig MEDIA_SUPPORT
 	tristate "Multimedia support"
 	depends on HAS_IOMEM
+	select SYNC_FILE
 	help
 	  If you want to use Webcams, Video grabber devices and/or TV devices
 	  enable this option and other options below.
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index ea83126..29aa9d4 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1279,6 +1279,22 @@ static int __buf_prepare(struct vb2_buffer *vb, const void *pb)
 	return 0;
 }
 
+static int __get_num_ready_buffers(struct vb2_queue *q)
+{
+	struct vb2_buffer *vb;
+	int ready_count = 0;
+
+	/* count num of buffers ready in front of the queued_list */
+	list_for_each_entry(vb, &q->queued_list, queued_entry) {
+		if (vb->in_fence && !dma_fence_is_signaled(vb->in_fence))
+			break;
+
+		ready_count++;
+	}
+
+	return ready_count;
+}
+
 int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
 {
 	struct vb2_buffer *vb;
@@ -1324,8 +1340,15 @@ static int vb2_start_streaming(struct vb2_queue *q)
 	 * If any buffers were queued before streamon,
 	 * we can now pass them to driver for processing.
 	 */
-	list_for_each_entry(vb, &q->queued_list, queued_entry)
+	list_for_each_entry(vb, &q->queued_list, queued_entry) {
+		if (vb->state != VB2_BUF_STATE_QUEUED)
+			continue;
+
+		if (vb->in_fence && !dma_fence_is_signaled(vb->in_fence))
+			break;
+
 		__enqueue_in_driver(vb);
+	}
 
 	/* Tell the driver to start streaming */
 	q->start_streaming_called = 1;
@@ -1369,33 +1392,55 @@ static int vb2_start_streaming(struct vb2_queue *q)
 
 static int __vb2_core_qbuf(struct vb2_buffer *vb, struct vb2_queue *q)
 {
+	struct vb2_buffer *b;
 	int ret;
 
 	/*
 	 * If already streaming, give the buffer to driver for processing.
 	 * If not, the buffer will be given to driver on next streamon.
 	 */
-	if (q->start_streaming_called)
-		__enqueue_in_driver(vb);
 
-	/*
-	 * If streamon has been called, and we haven't yet called
-	 * start_streaming() since not enough buffers were queued, and
-	 * we now have reached the minimum number of queued buffers,
-	 * then we can finally call start_streaming().
-	 */
-	if (q->streaming && !q->start_streaming_called &&
-	    q->queued_count >= q->min_buffers_needed) {
-		ret = vb2_start_streaming(q);
-		if (ret)
-			return ret;
+	if (q->start_streaming_called) {
+		list_for_each_entry(b, &q->queued_list, queued_entry) {
+			if (b->state != VB2_BUF_STATE_QUEUED)
+				continue;
+
+			if (b->in_fence && !dma_fence_is_signaled(b->in_fence))
+				break;
+
+			__enqueue_in_driver(b);
+		}
+	} else {
+		/*
+		 * If streamon has been called, and we haven't yet called
+		 * start_streaming() since not enough buffers were queued, and
+		 * we now have reached the minimum number of queued buffers
+		 * that are ready, then we can finally call start_streaming().
+		 */
+		if (q->streaming &&
+		    __get_num_ready_buffers(q) >= q->min_buffers_needed) {
+			ret = vb2_start_streaming(q);
+			if (ret)
+				return ret;
+		}
 	}
 
 	dprintk(1, "qbuf of buffer %d succeeded\n", vb->index);
 	return 0;
 }
 
-int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
+static void vb2_qbuf_fence_cb(struct dma_fence *f, struct dma_fence_cb *cb)
+{
+	struct vb2_buffer *vb = container_of(cb, struct vb2_buffer, fence_cb);
+
+	dma_fence_put(vb->in_fence);
+	vb->in_fence = NULL;
+
+	__vb2_core_qbuf(vb, vb->vb2_queue);
+}
+
+int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
+		  struct dma_fence *fence)
 {
 	struct vb2_buffer *vb;
 	int ret;
@@ -1436,6 +1481,11 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
 	if (pb)
 		call_void_bufop(q, fill_user_buffer, vb, pb);
 
+	vb->in_fence = fence;
+	if (fence && !dma_fence_add_callback(fence, &vb->fence_cb,
+					     vb2_qbuf_fence_cb))
+		return 0;
+
 	return __vb2_core_qbuf(vb, q);
 }
 EXPORT_SYMBOL_GPL(vb2_core_qbuf);
@@ -1647,6 +1697,7 @@ EXPORT_SYMBOL_GPL(vb2_core_dqbuf);
 static void __vb2_queue_cancel(struct vb2_queue *q)
 {
 	unsigned int i;
+	struct vb2_buffer *vb;
 
 	/*
 	 * Tell driver to stop all transactions and release all queued
@@ -1669,6 +1720,14 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 		WARN_ON(atomic_read(&q->owned_by_drv_count));
 	}
 
+	list_for_each_entry(vb, &q->queued_list, queued_entry) {
+		if (vb->in_fence) {
+			dma_fence_remove_callback(vb->in_fence, &vb->fence_cb);
+			dma_fence_put(vb->in_fence);
+			vb->in_fence = NULL;
+		}
+	}
+
 	q->streaming = 0;
 	q->start_streaming_called = 0;
 	q->queued_count = 0;
@@ -1735,7 +1794,7 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
 	 * Tell driver to start streaming provided sufficient buffers
 	 * are available.
 	 */
-	if (q->queued_count >= q->min_buffers_needed) {
+	if (__get_num_ready_buffers(q) >= q->min_buffers_needed) {
 		ret = v4l_vb2q_enable_media_source(q);
 		if (ret)
 			return ret;
@@ -2250,7 +2309,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
 		 * Queue all buffers.
 		 */
 		for (i = 0; i < q->num_buffers; i++) {
-			ret = vb2_core_qbuf(q, i, NULL);
+			ret = vb2_core_qbuf(q, i, NULL, NULL);
 			if (ret)
 				goto err_reqbufs;
 			fileio->bufs[i].queued = 1;
@@ -2429,7 +2488,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
 
 		if (copy_timestamp)
 			b->timestamp = ktime_get_ns();
-		ret = vb2_core_qbuf(q, index, NULL);
+		ret = vb2_core_qbuf(q, index, NULL, NULL);
 		dprintk(5, "vb2_dbuf result: %d\n", ret);
 		if (ret)
 			return ret;
@@ -2532,7 +2591,7 @@ static int vb2_thread(void *data)
 		if (copy_timestamp)
 			vb->timestamp = ktime_get_ns();;
 		if (!threadio->stop)
-			ret = vb2_core_qbuf(q, vb->index, NULL);
+			ret = vb2_core_qbuf(q, vb->index, NULL, NULL);
 		call_void_qop(q, wait_prepare, q);
 		if (ret || threadio->stop)
 			break;
diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
index 110fb45..e6ad77f 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -23,6 +23,7 @@
 #include <linux/sched.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
+#include <linux/sync_file.h>
 
 #include <media/v4l2-dev.h>
 #include <media/v4l2-fh.h>
@@ -560,6 +561,7 @@ EXPORT_SYMBOL_GPL(vb2_create_bufs);
 
 int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 {
+	struct dma_fence *fence = NULL;
 	int ret;
 
 	if (vb2_fileio_is_active(q)) {
@@ -568,7 +570,18 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
 	}
 
 	ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
-	return ret ? ret : vb2_core_qbuf(q, b->index, b);
+	if (ret)
+		return ret;
+
+	if (b->flags & V4L2_BUF_FLAG_IN_FENCE) {
+		fence = sync_file_get_fence(b->fence_fd);
+		if (!fence) {
+			dprintk(1, "failed to get in-fence from fd\n");
+			return -EINVAL;
+		}
+	}
+
+	return ret ? ret : vb2_core_qbuf(q, b->index, b, fence);
 }
 EXPORT_SYMBOL_GPL(vb2_qbuf);
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index cb97c22..aa43e43 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/dma-buf.h>
+#include <linux/dma-fence.h>
 
 #define VB2_MAX_FRAME	(32)
 #define VB2_MAX_PLANES	(8)
@@ -259,6 +260,9 @@ struct vb2_buffer {
 
 	struct list_head	queued_entry;
 	struct list_head	done_entry;
+
+	struct dma_fence	*in_fence;
+	struct dma_fence_cb	fence_cb;
 #ifdef CONFIG_VIDEO_ADV_DEBUG
 	/*
 	 * Counters for how often these buffer-related ops are
@@ -727,7 +731,8 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
  * The return values from this function are intended to be directly returned
  * from vidioc_qbuf handler in driver.
  */
-int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
+int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
+		  struct dma_fence *fence);
 
 /**
  * vb2_core_dqbuf() - Dequeue a buffer to the userspace
-- 
2.9.4




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