usb: gadget: uvc: configfs: Add bFrameIndex attributes

- 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 frame size of the gadget).
After the negotiation the host driver will set the user or application
selected frame size, while the gadget is actually set to the first frame
size.

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 configfs 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>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index a6cc8d6d398ebf002fc286f3b581cea2c0f3d9c3..809765bd95730649f89030c4441831559da8da51 100644 (file)
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -189,6 +189,10 @@ 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
@@ -240,6 +244,10 @@ 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 5cee8aca37341261957cbcd6cca6a79fd8ce33e8..b8763343dcae49ab47a7012739868118e84c36ae 100644 (file)
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -868,6 +868,8 @@ 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)
 {
@@ -915,6 +917,8 @@ 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;
@@ -1146,6 +1150,41 @@ 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,
@@ -1294,6 +1333,7 @@ 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,
@@ -1373,6 +1413,22 @@ static void uvcg_frame_drop(struct config_group *group, struct config_item *item
        config_item_put(item);
 }
 
+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>
  */