Add support of read() call from userspace by implementing
uvc_v4l2_read() with vb2_read() helper.
Signed-off-by: Hugues Fruchet <hugues.fruc...@st.com>
---
drivers/media/usb/uvc/uvc_queue.c | 15 ++++++++++++++-
drivers/media/usb/uvc/uvc_v4l2.c | 11 ++++++++---
drivers/media/usb/uvc/uvcvideo.h | 2 ++
3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_queue.c
b/drivers/media/usb/uvc/uvc_queue.c
index 682698e..0c8a0a8 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -227,7 +227,7 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum
v4l2_buf_type type,
int ret;
queue->queue.type = type;
- queue->queue.io_modes = VB2_MMAP | VB2_USERPTR;
+ queue->queue.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
queue->queue.drv_priv = queue;
queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
queue->queue.mem_ops = &vb2_vmalloc_memops;
@@ -361,6 +361,19 @@ int uvc_queue_streamoff(struct uvc_video_queue *queue,
enum v4l2_buf_type type)
return ret;
}
+ssize_t uvc_queue_read(struct uvc_video_queue *queue, struct file *file,
+ char __user *buf, size_t count, loff_t *ppos)
+{
+ ssize_t ret;
+
+ mutex_lock(&queue->mutex);
+ ret = vb2_read(&queue->queue, buf, count, ppos,
+ file->f_flags & O_NONBLOCK);
+ mutex_unlock(&queue->mutex);
+
+ return ret;
+}
+
int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma)
{
return vb2_mmap(&queue->queue, vma);
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 84be596..3866832 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -594,7 +594,8 @@ static int uvc_ioctl_querycap(struct file *file, void *fh,
strscpy(cap->driver, "uvcvideo", sizeof(cap->driver));
strscpy(cap->card, vdev->name, sizeof(cap->card));
usb_make_path(stream->dev->udev, cap->bus_info, sizeof(cap->bus_info));
- cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING
+ cap->capabilities = V4L2_CAP_DEVICE_CAPS | V4L2_CAP_STREAMING |
+ V4L2_CAP_READWRITE
| chain->caps;
return 0;
@@ -1434,8 +1435,12 @@ static long uvc_v4l2_compat_ioctl32(struct file *file,
static ssize_t uvc_v4l2_read(struct file *file, char __user *data,
size_t count, loff_t *ppos)
{
- uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_read: not implemented.\n");
- return -EINVAL;
+ struct uvc_fh *handle = file->private_data;
+ struct uvc_streaming *stream = handle->stream;
+
+ uvc_trace(UVC_TRACE_CALLS, "uvc_v4l2_read\n");
+
+ return uvc_queue_read(&stream->queue, file, data, count, ppos);
}
static int uvc_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index c7c1baa..5d0515c 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -766,6 +766,8 @@ struct uvc_buffer *uvc_queue_next_buffer(struct
uvc_video_queue *queue,
struct uvc_buffer *buf);
struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue);
void uvc_queue_buffer_release(struct uvc_buffer *buf);
+ssize_t uvc_queue_read(struct uvc_video_queue *queue, struct file *file,
+ char __user *buf, size_t count, loff_t *ppos);
int uvc_queue_mmap(struct uvc_video_queue *queue,
struct vm_area_struct *vma);
__poll_t uvc_queue_poll(struct uvc_video_queue *queue, struct file *file,
--
2.7.4
