[PATCH] usb: at91_udc: correct hanging while disconnecting usb cable

[Nicolas Ferre <nicolas.ferre@atmel.com>]

Correct hanging while disconnecting the USB device 
cable. Prevent a race between vbus and UDP interrupts.
This bug was tracked on at91sam9260ek boards.

Signed-off-by: Nicolas Ferre <nicolas.ferre@rfo.atmel.com> 
---

A usb resume interrupt was firing after the vbus 
interrupt : the IP was then already stoped and not able 
to deal with it (no more clock). A simple interrupt disabling 
is ok as the "end of bus reset" irq is non maskable and ok 
to resume the USB device IP.

--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -908,6 +908,7 @@ static void pullup(struct at91_udc *udc,
 
 	if (is_on) {
 		clk_on(udc);
+		at91_udp_write(udc, AT91_UDP_ICR, AT91_UDP_RXRSM);
 		at91_udp_write(udc, AT91_UDP_TXVC, 0);
 		if (cpu_is_at91rm9200())
 			at91_set_gpio_value(udc->board.pullup_pin, 1);
@@ -925,6 +926,7 @@ static void pullup(struct at91_udc *udc,
 		}
 	} else {
 		stop_activity(udc);
+		at91_udp_write(udc, AT91_UDP_IDR, AT91_UDP_RXRSM);
 		at91_udp_write(udc, AT91_UDP_TXVC, AT91_UDP_TXVC_TXVDIS);
 		if (cpu_is_at91rm9200())
 			at91_set_gpio_value(udc->board.pullup_pin, 0);