usb: dwc2: gadget: For DDMA parse setup only after SetUp interrupt

Tests with various hosts show that depend on time difference between
host sending SETUP packet and IN/OUT token SW could get Xfercomplete
interrupt without SetUp interrupt. On the other hand, SW should parse
received SETUP packet only after ensuring that Host has moved to either
Data or Status stage of control transfer.

For this purpose added checking in the dwc2_hsotg_epint() function to
not handle xfercomplete and postpone SETUP packet analysis till SW's
getting of setup phase done interrupt.

Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/gadget.c

@@ -2838,6 +2838,16 @@ static void dwc2_hsotg_epint(struct dwc2_hsotg *hsotg, unsigned int idx,
 	if (idx == 0 && (ints & (DXEPINT_SETUP | DXEPINT_SETUP_RCVD)))
 		ints &= ~DXEPINT_XFERCOMPL;
 
+	/*
+	 * Don't process XferCompl interrupt in DDMA if EP0 is still in SETUP
+	 * stage and xfercomplete was generated without SETUP phase done
+	 * interrupt. SW should parse received setup packet only after host's
+	 * exit from setup phase of control transfer.
+	 */
+	if (using_desc_dma(hsotg) && idx == 0 && !hs_ep->dir_in &&
+	    hsotg->ep0_state == DWC2_EP0_SETUP && !(ints & DXEPINT_SETUP))
+		ints &= ~DXEPINT_XFERCOMPL;
+
 	if (ints & DXEPINT_XFERCOMPL) {
 		dev_dbg(hsotg->dev,
 			"%s: XferCompl: DxEPCTL=0x%08x, DXEPTSIZ=%08x\n",