usb: chipidea: udc: protect usb interrupt enable

We hit the problem with below sequence:
- ci_udc_vbus_session() update vbus_active flag and ci->driver
is valid,
- before calling the ci_hdrc_gadget_connect(),
usb_gadget_udc_stop() is called by application remove gadget
driver,
- ci_udc_vbus_session() will contine do ci_hdrc_gadget_connect() as
gadget_ready is 1, so udc interrupt is enabled, but ci->driver is
NULL.
- USB connection irq generated but ci->driver is NULL.

As udc irq only should be enabled when gadget driver is binded, so
add spinlock to protect the usb irq enable for vbus session handling.
Signed-off-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>

drivers/usb/chipidea/udc.c

@@ -1530,13 +1530,18 @@ static const struct usb_ep_ops usb_ep_ops = {
 static void ci_hdrc_gadget_connect(struct usb_gadget *_gadget, int is_active)
 {
 	struct ci_hdrc *ci = container_of(_gadget, struct ci_hdrc, gadget);
+	unsigned long flags;
 
 	if (is_active) {
 		pm_runtime_get_sync(&_gadget->dev);
 		hw_device_reset(ci);
-		hw_device_state(ci, ci->ep0out->qh.dma);
-		usb_gadget_set_state(_gadget, USB_STATE_POWERED);
-		usb_udc_vbus_handler(_gadget, true);
+		spin_lock_irqsave(&ci->lock, flags);
+		if (ci->driver) {
+			hw_device_state(ci, ci->ep0out->qh.dma);
+			usb_gadget_set_state(_gadget, USB_STATE_POWERED);
+			usb_udc_vbus_handler(_gadget, true);
+		}
+		spin_unlock_irqrestore(&ci->lock, flags);
 	} else {
 		usb_udc_vbus_handler(_gadget, false);
 		if (ci->driver)
@@ -1555,19 +1560,16 @@ static int ci_udc_vbus_session(struct usb_gadget *_gadget, int is_active)
 {
 	struct ci_hdrc *ci = container_of(_gadget, struct ci_hdrc, gadget);
 	unsigned long flags;
-	int gadget_ready = 0;
 
 	spin_lock_irqsave(&ci->lock, flags);
 	ci->vbus_active = is_active;
-	if (ci->driver)
-		gadget_ready = 1;
 	spin_unlock_irqrestore(&ci->lock, flags);
 
 	if (ci->usb_phy)
 		usb_phy_set_charger_state(ci->usb_phy, is_active ?
 			USB_CHARGER_PRESENT : USB_CHARGER_ABSENT);
 
-	if (gadget_ready)
+	if (ci->driver)
 		ci_hdrc_gadget_connect(_gadget, is_active);
 
 	return 0;
@@ -1827,6 +1829,7 @@ static int ci_udc_stop(struct usb_gadget *gadget)
 	unsigned long flags;
 
 	spin_lock_irqsave(&ci->lock, flags);
+	ci->driver = NULL;
 
 	if (ci->vbus_active) {
 		hw_device_state(ci, 0);
@@ -1839,7 +1842,6 @@ static int ci_udc_stop(struct usb_gadget *gadget)
 		pm_runtime_put(&ci->gadget.dev);
 	}
 
-	ci->driver = NULL;
 	spin_unlock_irqrestore(&ci->lock, flags);
 
 	ci_udc_stop_for_otg_fsm(ci);