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[7/8] usb: gadget: uvc: configfs: Add bFrameIndex attributes

Message ID 20180801002909.2890-8-laurent.pinchart@ideasonboard.com (mailing list archive)
State New, archived
Headers show
Series usb: gadget: uvc: Improve configfs support | expand

Commit Message

Laurent Pinchart Aug. 1, 2018, 12:29 a.m. UTC 
From: Joel Pepper <joel.pepper@rwth-aachen.de>

- Add bFrameIndex as a UVCG_FRAME_ATTR_RO for each frame size.
- Automatically assign ascending bFrameIndex to each frame in a format.

Before all "bFrameindex" attributes were set to "1" with no way to
configure the gadget otherwise. This resulted in the host always
negotiating for bFrameIndex 1 (i.e. the first framesize of the gadget).
After the negotiation the host driver will set the user or application
selected framesize, while the gadget is actually set to the first
framesize.

Now, when the containing format is linked into the streaming header,
iterate over all child frame descriptors and assign ascending indices.
The automatically assigned indices can be read from the new read only
bFrameIndex configsfs attribute in each frame descriptor item.

Signed-off-by: Joel Pepper <joel.pepper@rwth-aachen.de>
[Simplified documentation, renamed function, blank space update]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 Documentation/ABI/testing/configfs-usb-gadget-uvc |  8 ++++
 drivers/usb/gadget/function/uvc_configfs.c        | 56 +++++++++++++++++++++++
 2 files changed, 64 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index 9896c8aa0e14..1efeb2e835ea 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -181,6 +181,10 @@  Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Specific MJPEG frame descriptors
 
+		bFrameIndex		- unique id for this framedescriptor;
+					only defined after parent format is
+					linked into the streaming header;
+					read-only
 		dwFrameInterval		- indicates how frame interval can be
 					programmed; a number of values
 					separated by newline can be specified
@@ -232,6 +236,10 @@  Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Specific uncompressed frame descriptors
 
+		bFrameIndex		- unique id for this framedescriptor;
+					only defined after parent format is
+					linked into the streaming header;
+					read-only
 		dwFrameInterval		- indicates how frame interval can be
 					programmed; a number of values
 					separated by newline can be specified
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index 90de6418209b..9af4cda27865 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -841,6 +841,8 @@  static struct uvcg_streaming_header *to_uvcg_streaming_header(struct config_item
 	return container_of(item, struct uvcg_streaming_header, item);
 }
 
+static void uvcg_format_set_indices(struct config_group *fmt);
+
 static int uvcg_streaming_header_allow_link(struct config_item *src,
 					    struct config_item *target)
 {
@@ -888,6 +890,8 @@  static int uvcg_streaming_header_allow_link(struct config_item *src,
 	if (!target_fmt)
 		goto out;
 
+	uvcg_format_set_indices(to_config_group(target));
+
 	format_ptr = kzalloc(sizeof(*format_ptr), GFP_KERNEL);
 	if (!format_ptr) {
 		ret = -ENOMEM;
@@ -1126,6 +1130,41 @@  end:									\
 									\
 UVC_ATTR(uvcg_frame_, cname, aname);
 
+static ssize_t uvcg_frame_b_frame_index_show(struct config_item *item,
+					     char *page)
+{
+	struct uvcg_frame *f = to_uvcg_frame(item);
+	struct uvcg_format *fmt;
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct config_item *fmt_item;
+	struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;
+	int result;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	fmt_item = f->item.ci_parent;
+	fmt = to_uvcg_format(fmt_item);
+
+	if (!fmt->linked) {
+		result = -EBUSY;
+		goto out;
+	}
+
+	opts_item = fmt_item->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d\n", f->frame.b_frame_index);
+	mutex_unlock(&opts->lock);
+
+out:
+	mutex_unlock(su_mutex);
+	return result;
+}
+
+UVC_ATTR_RO(uvcg_frame_, b_frame_index, bFrameIndex);
+
 #define noop_conversion(x) (x)
 
 UVCG_FRAME_ATTR(bm_capabilities, bmCapabilities, noop_conversion,
@@ -1274,6 +1313,7 @@  static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
 UVC_ATTR(uvcg_frame_, dw_frame_interval, dwFrameInterval);
 
 static struct configfs_attribute *uvcg_frame_attrs[] = {
+	&uvcg_frame_attr_b_frame_index,
 	&uvcg_frame_attr_bm_capabilities,
 	&uvcg_frame_attr_w_width,
 	&uvcg_frame_attr_w_height,
@@ -1352,6 +1392,22 @@  static void uvcg_frame_drop(struct config_group *group, struct config_item *item
 	mutex_unlock(&opts->lock);
 }
 
+static void uvcg_format_set_indices(struct config_group *fmt)
+{
+	struct config_item *ci;
+	unsigned int i = 1;
+
+	list_for_each_entry(ci, &fmt->cg_children, ci_entry) {
+		struct uvcg_frame *frm;
+
+		if (ci->ci_type != &uvcg_frame_type)
+			continue;
+
+		frm = to_uvcg_frame(ci);
+		frm->frame.b_frame_index = i++;
+	}
+}
+
 /* -----------------------------------------------------------------------------
  * streaming/uncompressed/<NAME>
  */