[PATCH 4.14 71/82] usb: dwc2: gadget: Fix sending zero length packet in DDMA mode.

Greg Kroah-Hartman
2021-07-26T16:00:02Z

From: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>

commit d53dc38857f6dbefabd9eecfcbf67b6eac9a1ef4 upstream.

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

--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -2702,12 +2702,14 @@ static void dwc2_hsotg_complete_in(struc
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) {