linux-kernel - [PATCH] usb: dwc3: Prevent indefinite sleep in _dwc3_set

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Message-ID: <1519730526-22274-1-git-send-email-rogerq@ti.com>
Date:   Tue, 27 Feb 2018 13:22:06 +0200
From:   Roger Quadros <rogerq@...com>
To:     <balbi@...nel.org>
CC:     <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Roger Quadros <rogerq@...com>
Subject: [PATCH] usb: dwc3: Prevent indefinite sleep in _dwc3_set_mode during suspend/resume

In the following test we get stuck by sleeping forever in _dwc3_set_mode()
after which dual-role switching doesn't work.

On dra7-evm's dual-role port,
- Load g_zero gadget driver and enumerate to host
- suspend to mem
- disconnect USB cable to host and connect otg cable with Pen drive in it.
- resume system
- we sleep indefinitely in _dwc3_set_mode due to.
  dwc3_gadget_exit()->usb_del_gadget_udc()->udc_stop()->
	dwc3_gadget_stop()->wait_event_lock_irq()

Let's clear the DWC3_EP_END_TRANSFER_PENDING flag on all endpoints
so we don't wait in dwc3_gadget_stop().

Signed-off-by: Roger Quadros <rogerq@...com>
---
 drivers/usb/dwc3/gadget.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 2bda4eb..0a360da 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3273,6 +3273,20 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 
 void dwc3_gadget_exit(struct dwc3 *dwc)
 {
+	int epnum;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	for (epnum = 2; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
+		struct dwc3_ep  *dep = dwc->eps[epnum];
+
+		if (!dep)
+			continue;
+
+		dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
+	}
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
 	usb_del_gadget_udc(&dwc->gadget);
 	dwc3_gadget_free_endpoints(dwc);
 	dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
-- 
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki