usb: dwc3: gadget: Set all ctrl fields of Transfer Control Blocks (TRB) to be LST

It turned out that current dwc3 gadget code is preparing multiple TRBs
for a transfer. Unfortunately, when multiple requests are in the same
queue, only for the last one the LST (last) ctrl bit is set.

Due to that dwc3 HW executes all TRBs up till the one marked as last.
Unfortunately, UMS requires call of ->complete callback after any send TRB.
This is the reason for "hangs" in executing UMS.

This code simplifies this situation and set each TRB's ctrl field bit to be
last (LST bit).

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index eb31cd93d622a5a6550afd9c5eb153fb761c0c3b..a8335b3964cfcf59bb4ee058691a1f3d377ffa13 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -789,7 +789,6 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
        struct dwc3_request     *req, *n;
        u32                     trbs_left;
        u32                     max;
-       unsigned int            last_one = 0;
 
        BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM);
 
@@ -839,24 +838,14 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
        list_for_each_entry_safe(req, n, &dep->request_list, list) {
                unsigned        length;
                dma_addr_t      dma;
-               last_one = false;
 
                dma = req->request.dma;
                length = req->request.length;
-               trbs_left--;
-
-               if (!trbs_left)
-                       last_one = 1;
-
-               /* Is this the last request? */
-               if (list_is_last(&req->list, &dep->request_list))
-                       last_one = 1;
 
                dwc3_prepare_one_trb(dep, req, dma, length,
-                               last_one, false, 0);
+                                    true, false, 0);
 
-               if (last_one)
-                       break;
+               break;
        }
 }