USB: fsl_qe_udc: Fix oops on QE UDC probe failure

In case of probing errors the driver kfrees the udc_controller, but it
doesn't set the pointer to NULL.

When usb_gadget_register_driver is called, it checks for udc_controller
!= NULL, the check passes and the driver accesses nonexistent memory.
Fix this by setting udc_controller to NULL in case of errors.

While at it, also implement irq_of_parse_and_map()'s failure and cleanup
cases.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/fsl_qe_udc.c

diff --git a/drivers/usb/gadget/fsl_qe_udc.c b/drivers/usb/gadget/fsl_qe_udc.c
index d6c5bcd..e8f7862 100644
--- a/drivers/usb/gadget/fsl_qe_udc.c
+++ b/drivers/usb/gadget/fsl_qe_udc.c
@@ -2604,6 +2604,10 @@
 			(unsigned long)udc_controller);
 	/* request irq and disable DR  */
 	udc_controller->usb_irq = irq_of_parse_and_map(np, 0);
+	if (!udc_controller->usb_irq) {
+		ret = -EINVAL;
+		goto err_noirq;
+	}
 
 	ret = request_irq(udc_controller->usb_irq, qe_udc_irq, 0,
 				driver_name, udc_controller);
@@ -2625,6 +2629,8 @@
 err6:
 	free_irq(udc_controller->usb_irq, udc_controller);
 err5:
+	irq_dispose_mapping(udc_controller->usb_irq);
+err_noirq:
 	if (udc_controller->nullmap) {
 		dma_unmap_single(udc_controller->gadget.dev.parent,
 			udc_controller->nullp, 256,
@@ -2648,7 +2654,7 @@
 	iounmap(udc_controller->usb_regs);
 err1:
 	kfree(udc_controller);
-
+	udc_controller = NULL;
 	return ret;
 }
 
@@ -2710,6 +2716,7 @@
 	kfree(ep->txframe);
 
 	free_irq(udc_controller->usb_irq, udc_controller);
+	irq_dispose_mapping(udc_controller->usb_irq);
 
 	tasklet_kill(&udc_controller->rx_tasklet);