usb: chipidea: need to mask when writting endptflush and endptprime

ENDPTFLUSH and ENDPTPRIME registers are set by software and clear
by hardware. There is a bit for each endpoint. When we are setting
a bit for an endpoint we should make sure we do not touch other
endpoint bit. There is a race condition if the hardware clear the
bit between the read and the write in hw_write.

Cc: stable <stable@vger.kernel.org> # 3.11+
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NMatthieu CASTET <matthieu.castet@parrot.com>
Tested-by: NMichael Grzeschik <mgrzeschik@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/udc.c

@@ -105,7 +105,7 @@ static int hw_ep_flush(struct ci_hdrc *ci, int num, int dir)
 
 	do {
 		/* flush any pending transfer */
-		hw_write(ci, OP_ENDPTFLUSH, BIT(n), BIT(n));
+		hw_write(ci, OP_ENDPTFLUSH, ~0, BIT(n));
 		while (hw_read(ci, OP_ENDPTFLUSH, BIT(n)))
 			cpu_relax();
 	} while (hw_read(ci, OP_ENDPTSTAT, BIT(n)));
@@ -205,7 +205,7 @@ static int hw_ep_prime(struct ci_hdrc *ci, int num, int dir, int is_ctrl)
 	if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num)))
 		return -EAGAIN;
 
-	hw_write(ci, OP_ENDPTPRIME, BIT(n), BIT(n));
+	hw_write(ci, OP_ENDPTPRIME, ~0, BIT(n));
 
 	while (hw_read(ci, OP_ENDPTPRIME, BIT(n)))
 		cpu_relax();