usb: gadget: mv_udc: fix boot up hang

Fix boot up hang when enable udc without otg enabled.
The root cause is that the clock will be shut down when probe routine is
finished because of clock gating. When a gadget driver is registered at
this time, it will call mv_udc_start which in turn will call
mv_udc_vbus_session. If there is no cable attached at the boot up time,
the vbus is low, so it will call stop_activity path without clock
enabled which will cause system hang then.
Actually, we need't go this path when clock is disabled, what we need to
do is just jump out.

Signed-off-by: Neil Zhang <zhangwm@marvell.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/mv_udc_core.c b/drivers/usb/gadget/mv_udc_core.c
index 58edff9abcef28a483722fea817fc1b1a3265b6b..ad91de4d60d8694ad5e736f5e233b993c5113c3c 100644 (file)
--- a/drivers/usb/gadget/mv_udc_core.c
+++ b/drivers/usb/gadget/mv_udc_core.c
@@ -1221,12 +1221,16 @@ static int mv_udc_vbus_session(struct usb_gadget *gadget, int is_active)
                        udc_start(udc);
                }
        } else if (udc->driver && udc->softconnect) {
+               if (!udc->active)
+                       goto out;
+
                /* stop all the transfer in queue*/
                stop_activity(udc, udc->driver);
                udc_stop(udc);
                mv_udc_disable(udc);
        }
 
+out:
        spin_unlock_irqrestore(&udc->lock, flags);
        return retval;
 }