USB: at91_udc: correct hanging while disconnecting usb cable

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

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.

Signed-off-by: Nicolas Ferre <nicolas.ferre@rfo.atmel.com>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index a6adf7e..cd62b02 100644 (file)
--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -887,6 +887,7 @@ static void pullup(struct at91_udc *udc, int is_on)
 
        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);
@@ -904,6 +905,7 @@ static void pullup(struct at91_udc *udc, int is_on)
                }
        } 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);