usb: dwc3: gadget: don't wait for ep cmd IRQ

That IRQ is causing way too much trouble. We have
a different handling which was agreed with IP
provider and has been tested with FPGA and OMAP5.
Tested-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/gadget.c

@@ -555,9 +555,34 @@ static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
 	struct dwc3_request		*req;
 
-	if (!list_empty(&dep->req_queued))
+	if (!list_empty(&dep->req_queued)) {
 		dwc3_stop_active_transfer(dwc, dep->number);
 
+		/*
+		 * NOTICE: We are violating what the Databook says about the
+		 * EndTransfer command. Ideally we would _always_ wait for the
+		 * EndTransfer Command Completion IRQ, but that's causing too
+		 * much trouble synchronizing between us and gadget driver.
+		 *
+		 * We have discussed this with the IP Provider and it was
+		 * suggested to giveback all requests here, but give HW some
+		 * extra time to synchronize with the interconnect. We're using
+		 * an arbitraty 100us delay for that.
+		 *
+		 * Note also that a similar handling was tested by Synopsys
+		 * (thanks a lot Paul) and nothing bad has come out of it.
+		 * In short, what we're doing is:
+		 *
+		 * - Issue EndTransfer WITH CMDIOC bit set
+		 * - Wait 100us
+		 * - giveback all requests to gadget driver
+		 */
+		udelay(100);
+
+		req = next_request(&dep->req_queued);
+		dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
+	}
+
 	while (!list_empty(&dep->request_list)) {
 		req = next_request(&dep->request_list);
 
@@ -1735,43 +1760,6 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
 	}
 }
 
-static void dwc3_process_ep_cmd_complete(struct dwc3_ep *dep,
-		const struct dwc3_event_depevt *event)
-{
-	struct dwc3 *dwc = dep->dwc;
-	struct dwc3_event_depevt mod_ev = *event;
-
-	/*
-	 * We were asked to remove one request. It is possible that this
-	 * request and a few others were started together and have the same
-	 * transfer index. Since we stopped the complete endpoint we don't
-	 * know how many requests were already completed (and not yet)
-	 * reported and how could be done (later). We purge them all until
-	 * the end of the list.
-	 */
-	mod_ev.status = DEPEVT_STATUS_LST;
-	dwc3_cleanup_done_reqs(dwc, dep, &mod_ev, -ESHUTDOWN);
-	dep->flags &= ~DWC3_EP_BUSY;
-	/* pending requests are ignored and are queued on XferNotReady */
-}
-
-static void dwc3_ep_cmd_compl(struct dwc3_ep *dep,
-		const struct dwc3_event_depevt *event)
-{
-	u32 param = event->parameters;
-	u32 cmd_type = (param >> 8) & ((1 << 5) - 1);
-
-	switch (cmd_type) {
-	case DWC3_DEPCMD_ENDTRANSFER:
-		dwc3_process_ep_cmd_complete(dep, event);
-		break;
-	default:
-		printk(KERN_ERR "%s() unknown /unexpected type: %d\n",
-				__func__, cmd_type);
-		break;
-	};
-}
-
 static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		const struct dwc3_event_depevt *event)
 {
@@ -1853,7 +1841,7 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		dev_dbg(dwc->dev, "%s FIFO Overrun\n", dep->name);
 		break;
 	case DWC3_DEPEVT_EPCMDCMPLT:
-		dwc3_ep_cmd_compl(dep, event);
+		dev_vdbg(dwc->dev, "Endpoint Command Complete\n");
 		break;
 	}
 }