[PATCH] usb: dwc3: Clear DWC3_EVENT_PENDING when count is 0

[JaeHun Jung]

Sometimes very rarely, The count is 0 and the DWC3 flag is set has status.
It must not have these status. Because, It can make happen interrupt storming
status.
So, It have to clean up DWC3_EVENT_PENDING flags set when count is 0.
It means "There are no interrupts to handle.".

(struct dwc3_event_buffer *) ev_buf = 0xFFFFFF883DBF1180 (
	(void *) buf = 0xFFFFFFC00DBDD000 = end+0x337D000,
	(void *) cache = 0xFFFFFF8839F54080,
	(unsigned int) length = 0x1000,
	(unsigned int) lpos = 0x0,
	(unsigned int) count = 0x0,
	(unsigned int) flags = 0x00000001,
	(dma_addr_t) dma = 0x00000008BD7D7000,
	(struct dwc3 *) dwc = 0xFFFFFF8839CBC880,
	(u64) android_kabi_reserved1 = 0x0),

(time = 47557628930999, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628931268, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628932383, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628932652, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628933768, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628934037, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628935152, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628935460, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628936575, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628936845, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628937960, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628938229, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628939345, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628939652, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628940768, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628941037, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628942152, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628942422, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628943537, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628943806, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628944922, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628945229, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628946345, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628946614, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),
(time = 47557628947729, irq = 165, fn = dwc3_interrupt, latency = 0, en = 1),
(time = 47557628947999, irq = 165, fn = dwc3_interrupt, latency = 0, en = 3),

Signed-off-by: JaeHun Jung <jh0801.jung@xxxxxxxxxxx>
---
 drivers/usb/dwc3/gadget.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 789976567f9f..5d2d5a9b9915 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4355,8 +4355,11 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 	 * irq event handler completes before caching new event to prevent
 	 * losing events.
 	 */
-	if (evt->flags & DWC3_EVENT_PENDING)
+	if (evt->flags & DWC3_EVENT_PENDING) {
+		if (!evt->count)
+			evt->flags &= ~DWC3_EVENT_PENDING;
 		return IRQ_HANDLED;
+	}
 
 	count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
 	count &= DWC3_GEVNTCOUNT_MASK;
-- 
2.31.1