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From d9feef974e0d8cb6842533c92476a1b32a41ba31 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Tue, 31 Mar 2020 01:40:42 -0700
Subject: [PATCH] usb: dwc3: gadget: Continue to process pending requests
Git-commit: d9feef974e0d8cb6842533c92476a1b32a41ba31
Patch-mainline: v5.8-rc1
References: git-fixes

If there are still pending requests because no TRB was available,
prepare more when started requests are completed.

Introduce dwc3_gadget_ep_should_continue() to check for incomplete and
pending requests to resume updating new TRBs to the controller's TRB
cache.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/dwc3/gadget.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a0555252dee0..20b593ea140f 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2600,10 +2600,8 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
 
 	req->request.actual = req->request.length - req->remaining;
 
-	if (!dwc3_gadget_ep_request_completed(req)) {
-		__dwc3_gadget_kick_transfer(dep);
+	if (!dwc3_gadget_ep_request_completed(req))
 		goto out;
-	}
 
 	dwc3_gadget_giveback(dep, req, status);
 
@@ -2627,6 +2625,24 @@ static void dwc3_gadget_ep_cleanup_completed_requests(struct dwc3_ep *dep,
 	}
 }
 
+static bool dwc3_gadget_ep_should_continue(struct dwc3_ep *dep)
+{
+	struct dwc3_request	*req;
+
+	if (!list_empty(&dep->pending_list))
+		return true;
+
+	/*
+	 * We only need to check the first entry of the started list. We can
+	 * assume the completed requests are removed from the started list.
+	 */
+	req = next_request(&dep->started_list);
+	if (!req)
+		return false;
+
+	return !dwc3_gadget_ep_request_completed(req);
+}
+
 static void dwc3_gadget_endpoint_frame_from_event(struct dwc3_ep *dep,
 		const struct dwc3_event_depevt *event)
 {
@@ -2656,6 +2672,8 @@ static void dwc3_gadget_endpoint_transfer_in_progress(struct dwc3_ep *dep,
 
 	if (stop)
 		dwc3_stop_active_transfer(dep, true, true);
+	else if (dwc3_gadget_ep_should_continue(dep))
+		__dwc3_gadget_kick_transfer(dep);
 
 	/*
 	 * WORKAROUND: This is the 2nd half of U1/U2 -> U0 workaround.
-- 
2.31.1