Implement mmapped streaming reception

From: Mauro Carvalho Chehab <mchehab@infradead.org>

Add capabilities to the library and to the driver to receive video streams.
Library will use a callback, called every time a new buffer is reported by
dqbuf.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

3 files changed, 93 insertions, 23 deletions

diff --git a/v4l2-apps/lib/v4l2_driver.c b/v4l2-apps/lib/v4l2_driver.c
index a73d6a3f5..7d6b549a2 100644
--- a/v4l2-apps/lib/v4l2_driver.c
+++ b/v4l2-apps/lib/v4l2_driver.c
@@ -169,7 +169,7 @@ int v4l2_open (char *device, int debug, struct v4l2_driver *drv)
 
 	drv->debug=debug;
 
-	if ((drv->fd = open(device, O_RDWR | O_NONBLOCK )) < 0) {
+	if ((drv->fd = open(device, O_RDWR )) < 0) {
 		perror("Couldn't open video0");
 		return(errno);
 	}
@@ -652,23 +652,57 @@ int v4l2_mmap_bufs(struct v4l2_driver *drv, unsigned int num_buffers)
 	return 0;
 }
 
-/* Returns -1 if all buffers are being used, 0 if ok and errno if error */
-int v4l2_qbuf(struct v4l2_driver *drv)
+int v4l2_rcvbuf(struct v4l2_driver *drv, v4l2_recebe_buffer *rec_buf)
 {
-	if (((drv->currq+1) % drv->reqbuf.count) == drv->waitq)
-		return -1;
+	int ret;
 
-	if (xioctl(drv->fd,VIDIOC_QBUF,&drv->v4l2_bufs[(drv->currq) % drv->reqbuf.count])<0)
-		return errno;
+	struct v4l2_buffer buf;
+	memset (&buf, 0, sizeof(buf));
+
+	buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	buf.memory = V4L2_MEMORY_MMAP;
+
+	if (-1 == xioctl (drv->fd, VIDIOC_DQBUF, &buf)) {
+		switch (errno) {
+		case EAGAIN:
+			return 0;
+
+		case EIO:
+			/* Could ignore EIO, see spec. */
+
+			/* fall through */
+
+		default:
+			perror ("dqbuf");
+			return errno;
+		}
+	}
+	prt_buf_info("DQBUF",&buf);
+
+	assert (buf.index < drv->n_bufs);
+
+	ret = rec_buf (&buf,&drv->bufs[buf.index]);
+
+	if (ret) {
+		v4l2_free_bufs(drv);
+		return ret;
+	}
 
+	if (-1 == xioctl (drv->fd, VIDIOC_QBUF, &buf)) {
+		perror ("qbuf");
+		return errno;
+	}
 	return 0;
 }
 
+
 int v4l2_start_streaming(struct v4l2_driver *drv)
 {
 	uint32_t	i;
         struct v4l2_buffer buf;
 
+	if (drv->debug)
+		printf("Activating %d queues\n", drv->n_bufs);
 	for (i = 0; i < drv->n_bufs; i++) {
 		int res;
 
@@ -678,24 +712,19 @@ int v4l2_start_streaming(struct v4l2_driver *drv)
 		buf.index  = i;
 
 		res = xioctl (drv->fd, VIDIOC_QBUF, &buf);
-prt_buf_info("***QBUF",&buf);
-printf("res=%d, errno=%d\n", res,errno);
-	}
-#if 0
-printf("Activating %d queues\n", drv->n_bufs);
-	/* Put all buffers int queue state */
-	for (i = 0; i < drv->n_bufs; i++) {
-prt_buf_info("***QBUF",drv->v4l2_bufs[i]);
 
-		if (xioctl(drv->fd,VIDIOC_QBUF,drv->v4l2_bufs[i])<0) {
-			perror ("qbuf");
+		if (!res)
+			prt_buf_info("QBUF",&buf);
+		else {
+			perror("qbuf");
 			return errno;
 		}
-		if (drv->debug)
-			prt_buf_info("QBUF",drv->v4l2_bufs[i]);
 	}
-#endif
+
 	/* Activates stream */
+	if (drv->debug)
+		printf("Enabling streaming\n");
+
 	if (xioctl(drv->fd,VIDIOC_STREAMON,&drv->reqbuf.type)<0)
 		return errno;
 
diff --git a/v4l2-apps/lib/v4l2_driver.h b/v4l2-apps/lib/v4l2_driver.h
index 1df9da3ba..ef6a754f4 100644
--- a/v4l2-apps/lib/v4l2_driver.h
+++ b/v4l2-apps/lib/v4l2_driver.h
@@ -26,6 +26,8 @@ struct v4l2_t_buf {
 	size_t		length;
 };
 
+typedef int v4l2_recebe_buffer (struct v4l2_buffer *v4l2_buf, struct v4l2_t_buf *buf);
+
 struct v4l2_driver {
 	int				fd;	/* Driver descriptor */
 
@@ -72,3 +74,4 @@ int v4l2_mmap_bufs(struct v4l2_driver *drv, unsigned int num_buffers);
 int v4l2_free_bufs(struct v4l2_driver *drv);
 int v4l2_start_streaming(struct v4l2_driver *drv);
 int v4l2_stop_streaming(struct v4l2_driver *drv);
+int v4l2_rcvbuf(struct v4l2_driver *drv, v4l2_recebe_buffer *v4l2_rec_buf);
diff --git a/v4l2-apps/test/driver-test.c b/v4l2-apps/test/driver-test.c
index 32b676836..61f6b812a 100644
--- a/v4l2-apps/test/driver-test.c
+++ b/v4l2-apps/test/driver-test.c
@@ -18,11 +18,19 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#include <errno.h>
+
+int recebe_buffer (struct v4l2_buffer *v4l2_buf, struct v4l2_t_buf *buf)
+{
+
+	return 0;
+}
 
 int main(void)
 {
 	struct v4l2_driver drv;
 	struct drv_list *cur;
+	unsigned int count = 10, i;
 
 	if (v4l2_open ("/dev/video0", 1,&drv)<0) {
 		perror("open");
@@ -76,12 +84,42 @@ int main(void)
 
 	v4l2_mmap_bufs(&drv, 2);
 
-//	v4l2_start_streaming(&drv);
+	v4l2_start_streaming(&drv);
+
+	printf("Waiting for frames...\n");
+
+	for (i=0;i<count;i++) {
+		fd_set fds;
+		struct timeval tv;
+		int r;
 
-//sleep (1);
+		FD_ZERO (&fds);
+		FD_SET (drv.fd, &fds);
 
-//	v4l2_stop_streaming(&drv);
+		/* Timeout. */
+		tv.tv_sec = 2;
+		tv.tv_usec = 0;
+
+		r = select (drv.fd + 1, &fds, NULL, NULL, &tv);
+		if (-1 == r) {
+			if (EINTR == errno)
+				continue;
+
+			perror ("select");
+			return errno;
+		}
+
+		if (0 == r) {
+			fprintf (stderr, "select timeout\n");
+			return errno;
+		}
+
+		if (v4l2_rcvbuf(&drv, recebe_buffer))
+			break;
+	}
 
+	printf("stopping streaming\n");
+	v4l2_stop_streaming(&drv);
 
 	if (v4l2_close (&drv)<0) {
 		perror("close");