From b4b7ff4b08e691656c9d77c758fc355833128ac0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?=
 <emulatorman@parabola.nu>
Date: Wed, 20 Jan 2016 14:01:31 -0300
Subject: Linux-libre 4.4-gnu

---
 drivers/usb/dwc3/gadget.c | 64 +++++++++++++++++++++++++++++++----------------
 1 file changed, 43 insertions(+), 21 deletions(-)

(limited to 'drivers/usb/dwc3/gadget.c')

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 9c38e4b0a..a58376fd6 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -948,7 +948,6 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
 		dwc3_trace(trace_dwc3_gadget, "%s: endpoint busy", dep->name);
 		return -EBUSY;
 	}
-	dep->flags &= ~DWC3_EP_PENDING_REQUEST;
 
 	/*
 	 * If we are getting here after a short-out-packet we don't enqueue any
@@ -1050,6 +1049,8 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 	req->direction		= dep->direction;
 	req->epnum		= dep->number;
 
+	trace_dwc3_ep_queue(req);
+
 	/*
 	 * We only add to our list of requests now and
 	 * start consuming the list once we get XferNotReady
@@ -1069,6 +1070,20 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 
 	list_add_tail(&req->list, &dep->request_list);
 
+	/*
+	 * If there are no pending requests and the endpoint isn't already
+	 * busy, we will just start the request straight away.
+	 *
+	 * This will save one IRQ (XFER_NOT_READY) and possibly make it a
+	 * little bit faster.
+	 */
+	if (!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+			!usb_endpoint_xfer_int(dep->endpoint.desc) &&
+			!(dep->flags & DWC3_EP_BUSY)) {
+		ret = __dwc3_gadget_kick_transfer(dep, 0, true);
+		goto out;
+	}
+
 	/*
 	 * There are a few special cases:
 	 *
@@ -1096,10 +1111,10 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 		}
 
 		ret = __dwc3_gadget_kick_transfer(dep, 0, true);
-		if (ret && ret != -EBUSY)
-			dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
-					dep->name);
-		return ret;
+		if (!ret)
+			dep->flags &= ~DWC3_EP_PENDING_REQUEST;
+
+		goto out;
 	}
 
 	/*
@@ -1113,10 +1128,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 		WARN_ON_ONCE(!dep->resource_index);
 		ret = __dwc3_gadget_kick_transfer(dep, dep->resource_index,
 				false);
-		if (ret && ret != -EBUSY)
-			dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
-					dep->name);
-		return ret;
+		goto out;
 	}
 
 	/*
@@ -1124,14 +1136,17 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 	 * right away, otherwise host will not know we have streams to be
 	 * handled.
 	 */
-	if (dep->stream_capable) {
+	if (dep->stream_capable)
 		ret = __dwc3_gadget_kick_transfer(dep, 0, true);
-		if (ret && ret != -EBUSY)
-			dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
-					dep->name);
-	}
 
-	return 0;
+out:
+	if (ret && ret != -EBUSY)
+		dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
+				dep->name);
+	if (ret == -EBUSY)
+		ret = 0;
+
+	return ret;
 }
 
 static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
@@ -1159,8 +1174,6 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
 		goto out;
 	}
 
-	trace_dwc3_ep_queue(req);
-
 	ret = __dwc3_gadget_ep_queue(dep, req);
 
 out:
@@ -1960,6 +1973,14 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
 
 		dwc->u1u2 = 0;
 	}
+
+	if (!usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
+		int ret;
+
+		ret = __dwc3_gadget_kick_transfer(dep, 0, is_xfer_complete);
+		if (!ret || ret == -EBUSY)
+			return;
+	}
 }
 
 static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
@@ -1997,15 +2018,16 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
 			dwc3_gadget_start_isoc(dwc, dep, event);
 		} else {
+			int active;
 			int ret;
 
+			active = event->status & DEPEVT_STATUS_TRANSFER_ACTIVE;
+
 			dwc3_trace(trace_dwc3_gadget, "%s: reason %s",
-					dep->name, event->status &
-					DEPEVT_STATUS_TRANSFER_ACTIVE
-					? "Transfer Active"
+					dep->name, active ? "Transfer Active"
 					: "Transfer Not Active");
 
-			ret = __dwc3_gadget_kick_transfer(dep, 0, 1);
+			ret = __dwc3_gadget_kick_transfer(dep, 0, !active);
 			if (!ret || ret == -EBUSY)
 				return;
 
-- 
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