We now have a mechanism to signal the UDC driver to reply to a control
OUT request with STALL or ACK, and we have packaged the setup stage data
and the data stage data of a control OUT request into a single
UVC_EVENT_DATA for userspace to consume. The ioctl UVCIOC_SEND_RESPONSE
in the case of a control OUT request sends a response to the data stage,
and so the ioctl now notifies the UDC driver to reply with STALL or ACK.
In the case of a control IN request, the ioctl sends the UVC data as
before.
Also tell the UDC to delay the status stage for this to work.
Signed-off-by: Paul Elder <paul.elder@xxxxxxxxxxxxxxxx>
---
No change from v4
No change from v3
Changes from v2:
- calling usb_ep_set_halt in uvc_send_response if data->length < 0 is
now common for both IN and OUT transfers so make that check common
- remove now unnecessary field setting for the usb_request to be queued
for the status stage
Changes from v1:
- remove usb_ep_delay_status call from the old proposed API
- changed portions of uvc_send_response to match v2 API
- remove UDC warning that send_response is not implemented
drivers/usb/gadget/function/f_uvc.c | 4 ++--
drivers/usb/gadget/function/uvc_v4l2.c | 23 +++++++++++++++++------
2 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 58ed191f636e..053808b01d48 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -209,14 +209,13 @@ uvc_function_ep0_complete(struct usb_ep *ep, struct usb_request *req)
struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
if (uvc->event_setup_out) {
- uvc->event_setup_out = 0;
-
memset(&v4l2_event, 0, sizeof(v4l2_event));
v4l2_event.type = UVC_EVENT_DATA;
uvc_event->data.length = req->actual;
memcpy(&uvc_event->data.data, req->buf, req->actual);
memcpy(&uvc_event->data.setup, &uvc->control_setup,
sizeof(uvc_event->data.setup));
+
v4l2_event_queue(&uvc->vdev, &v4l2_event);
}
}
@@ -251,6 +250,7 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
*/
req->length = uvc->event_length;
req->zero = 0;
+ req->explicit_status = 1;
usb_ep_queue(f->config->cdev->gadget->ep0, req, GFP_KERNEL);
} else {
struct v4l2_event v4l2_event;
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index ac48f49d9f10..353071869e15 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -35,15 +35,26 @@ uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
struct usb_composite_dev *cdev = uvc->func.config->cdev;
struct usb_request *req = uvc->control_req;
+ if (data->length < 0)
+ return usb_ep_set_halt(cdev->gadget->ep0);
+
/*
* For control OUT transfers the request has been enqueued synchronously
- * by the setup handler, there's nothing to be done here.
+ * by the setup handler, we just need to tell the UDC whether to ACK or
+ * STALL the control transfer.
*/
- if (uvc->event_setup_out)
- return 0;
-
- if (data->length < 0)
- return usb_ep_set_halt(cdev->gadget->ep0);
+ if (uvc->event_setup_out) {
+ /*
+ * The length field carries the control request status.
+ * Negative values signal a STALL and zero values an ACK.
+ * Positive values are not valid as there is no data to send
+ * back in the status stage.
+ */
+ if (data->length > 0)
+ return -EINVAL;
+
+ return usb_ep_queue(cdev->gadget->ep0, req, GFP_KERNEL);
+ }
req->length = min_t(unsigned int, uvc->event_length, data->length);
req->zero = data->length < uvc->event_length;
--
2.20.1
