From 36f84ffb45c75ff10442a9f8f2fd91dcf6c6f5dd Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Tue, 30 Sep 2014 10:39:14 -0500 Subject: [PATCH] usb: dwc3: ep0: fix Data Phase for transfer sizes aligned to wMaxPacketSize According to Section 8.5.3.2 of the USB 2.0 specification, a USB device must terminate a Data Phase with either a short packet or a ZLP (if the previous transfer was a multiple of wMaxPacketSize). For reference, here's what the USB 2.0 specification, section 8.5.3.2 says: " 8.5.3.2 Variable-length Data Stage A control pipe may have a variable-length data phase in which the host requests more data than is contained in the specified data structure. When all of the data structure is returned to the host, the function should indicate that the Data stage is ended by returning a packet that is shorter than the MaxPacketSize for the pipe. If the data structure is an exact multiple of wMaxPacketSize for the pipe, the function will return a zero-length packet to indicate the end of the Data stage. " Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/ep0.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index a47cc1e97fae..711b23019d54 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/drivers/usb/dwc3/ep0.c @@ -828,12 +828,19 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc, dwc3_ep0_stall_and_restart(dwc); } else { - /* - * handle the case where we have to send a zero packet. This - * seems to be case when req.length > maxpacket. Could it be? - */ - if (r) - dwc3_gadget_giveback(ep0, r, 0); + dwc3_gadget_giveback(ep0, r, 0); + + if (IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) && + ur->length && ur->zero) { + int ret; + + dwc->ep0_next_event = DWC3_EP0_COMPLETE; + + ret = dwc3_ep0_start_trans(dwc, epnum, + dwc->ctrl_req_addr, 0, + DWC3_TRBCTL_CONTROL_DATA); + WARN_ON(ret < 0); + } } } -- 2.20.1