From d53dc38857f6dbefabd9eecfcbf67b6eac9a1ef4 Mon Sep 17 00:00:00 2001
From: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Date: Tue, 20 Jul 2021 05:41:24 -0700
Subject: [PATCH] usb: dwc2: gadget: Fix sending zero length packet in DDMA mode.
Git-commit: d53dc38857f6dbefabd9eecfcbf67b6eac9a1ef4
Patch-mainline: v5.14-rc3
References: git-fixes

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")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Link: https://lore.kernel.org/r/967bad78c55dd2db1c19714eee3d0a17cf99d74a.1626777738.git.Minas.Harutyunyan@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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 74d25019272f..3146df6e6510 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) {
-- 
2.26.2