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From:   Wesley Cheng <quic_wcheng@quicinc.com>
To:     <balbi@kernel.org>, <gregkh@linuxfoundation.org>
CC:     <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <quic_jackp@quicinc.com>, <Thinh.Nguyen@synopsys.com>,
        Wesley Cheng <quic_wcheng@quicinc.com>
Subject: [PATCH] usb: dwc3: gadget: Wait for ep0 xfers to complete during dequeue
Date:   Tue, 8 Mar 2022 16:41:48 -0800
Message-ID: <20220309004148.12061-1-quic_wcheng@quicinc.com>
MIME-Version: 1.0
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From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

If the request being dequeued is currently active, then the current
logic is to issue a stop transfer command, and allow the command
completion to cleanup the cancelled list.  The DWC3 controller will
run into an end transfer command timeout if there is an ongoing EP0
transaction.  If this is the case, wait for the EP0 completion event
before proceeding to retry the endxfer command again.

Co-developed-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
 Patch discussion below:
   https://lore.kernel.org/linux-usb/1644836933-141376-1-git-send-email-dh10.jung@samsung.com/T/#t

 drivers/usb/dwc3/core.h   |  2 +-
 drivers/usb/dwc3/ep0.c    | 14 ++++++++++++++
 drivers/usb/dwc3/gadget.c | 13 ++++++++-----
 drivers/usb/dwc3/gadget.h |  1 +
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index eb9c1efced05..f557f5f36a7f 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -736,7 +736,7 @@ struct dwc3_ep {
 #define DWC3_EP_FIRST_STREAM_PRIMED	BIT(10)
 #define DWC3_EP_PENDING_CLEAR_STALL	BIT(11)
 #define DWC3_EP_TXFIFO_RESIZED		BIT(12)
-
+#define DWC3_EP_DELAY_STOP             BIT(13)
 	/* This last one is specific to EP0 */
 #define DWC3_EP0_DIR_IN			BIT(31)
 
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 658739410992..1064be5518f6 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -271,6 +271,7 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
 {
 	struct dwc3_ep			*dep;
 	int				ret;
+	int                             i;
 
 	complete(&dwc->ep0_in_setup);
 
@@ -279,6 +280,19 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
 			DWC3_TRBCTL_CONTROL_SETUP, false);
 	ret = dwc3_ep0_start_trans(dep);
 	WARN_ON(ret < 0);
+	for (i = 2; i < DWC3_ENDPOINTS_NUM; i++) {
+		struct dwc3_ep *dwc3_ep;
+
+		dwc3_ep = dwc->eps[i];
+		if (!dwc3_ep)
+			continue;
+
+		if (!(dwc3_ep->flags & DWC3_EP_DELAY_STOP))
+			continue;
+
+		dwc3_ep->flags &= ~DWC3_EP_DELAY_STOP;
+		dwc3_stop_active_transfer(dwc3_ep, true, true);
+	}
 }
 
 static struct dwc3_ep *dwc3_wIndex_to_dep(struct dwc3 *dwc, __le16 wIndex_le)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a0c883f19a41..ccef508b1296 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -654,9 +654,6 @@ static int dwc3_gadget_set_ep_config(struct dwc3_ep *dep, unsigned int action)
 	return dwc3_send_gadget_ep_cmd(dep, DWC3_DEPCMD_SETEPCONFIG, &params);
 }
 
-static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
-		bool interrupt);
-
 /**
  * dwc3_gadget_calc_tx_fifo_size - calculates the txfifo size value
  * @dwc: pointer to the DWC3 context
@@ -1899,6 +1896,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 	 */
 	if ((dep->flags & DWC3_EP_END_TRANSFER_PENDING) ||
 	    (dep->flags & DWC3_EP_WEDGE) ||
+	    (dep->flags & DWC3_EP_DELAY_STOP) ||
 	    (dep->flags & DWC3_EP_STALL)) {
 		dep->flags |= DWC3_EP_DELAY_START;
 		return 0;
@@ -2033,6 +2031,9 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 		if (r == req) {
 			struct dwc3_request *t;
 
+			if (dwc->ep0state != EP0_SETUP_PHASE && !dwc->delayed_status)
+				dep->flags |= DWC3_EP_DELAY_STOP;
+
 			/* wait until it is processed */
 			dwc3_stop_active_transfer(dep, true, true);
 
@@ -2116,7 +2117,8 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
 		list_for_each_entry_safe(req, tmp, &dep->started_list, list)
 			dwc3_gadget_move_cancelled_request(req, DWC3_REQUEST_STATUS_STALLED);
 
-		if (dep->flags & DWC3_EP_END_TRANSFER_PENDING) {
+		if (dep->flags & DWC3_EP_END_TRANSFER_PENDING ||
+		    (dep->flags & DWC3_EP_DELAY_STOP)) {
 			dep->flags |= DWC3_EP_PENDING_CLEAR_STALL;
 			return 0;
 		}
@@ -3596,7 +3598,7 @@ static void dwc3_reset_gadget(struct dwc3 *dwc)
 	}
 }
 
-static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
+void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 	bool interrupt)
 {
 	struct dwc3_gadget_ep_cmd_params params;
@@ -3604,6 +3606,7 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 	int ret;
 
 	if (!(dep->flags & DWC3_EP_TRANSFER_STARTED) ||
+		(dep->flags & DWC3_EP_DELAY_STOP) ||
 	    (dep->flags & DWC3_EP_END_TRANSFER_PENDING))
 		return;
 
diff --git a/drivers/usb/dwc3/gadget.h b/drivers/usb/dwc3/gadget.h
index 77df4b6d6c13..f763380e672e 100644
--- a/drivers/usb/dwc3/gadget.h
+++ b/drivers/usb/dwc3/gadget.h
@@ -116,6 +116,7 @@ int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
 		gfp_t gfp_flags);
 int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol);
 void dwc3_ep0_send_delayed_status(struct dwc3 *dwc);
+void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool interrupt);
 
 /**
  * dwc3_gadget_ep_get_transfer_index - Gets transfer index from HW