[PATCH v4] usb: dwc2: gadget: Fix sending zero length packet in DDMA mode.

Sending zero length packet in DDMA mode perform by DMA descriptor
by setting SP (short packet) flag.

For DDMA in function dwc2_hsotg_complete_in() does not need to send
zlp.

Tested by USBCV MSC tests.

Fixes: f71b5e2533de ("usb: dwc2: gadget: fix zero length packet transfers")
Signed-off-by: Minas Harutyunyan <redacted>
---
 Changes in v4:
 - In DDMA mode should go forward to move status OUT phase
 Changes in v3:
 - Updated mail recipient list
 Changes in v2:
 - Minor typo correction in comments

 drivers/usb/dwc2/gadget.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index c581ee41ac81..807c3cfec8e9 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c

@@ -2749,12 +2749,14 @@ static void dwc2_hsotg_complete_in(struct dwc2_hsotg *hsotg,
 		return;
 	}
 
-	/* Zlp for all endpoints, for ep0 only in DATA IN stage */
+	/* Zlp for all endpoints in non DDMA, for ep0 only in DATA IN stage */
 	if (hs_ep->send_zlp) {
-		dwc2_hsotg_program_zlp(hsotg, hs_ep);
 		hs_ep->send_zlp = 0;
-		/* transfer will be completed on next complete interrupt */
-		return;
+		if (!using_desc_dma(hsotg)) {
+			dwc2_hsotg_program_zlp(hsotg, hs_ep);
+			/* transfer will be completed on next complete interrupt */
+			return;
+		}
 	}
 
 	if (hs_ep->index == 0 && hsotg->ep0_state == DWC2_EP0_DATA_IN) {

base-commit: 00a738b86ec0c88ad4745f658966f951cbe4c885
-- 
2.11.0