MAILBOX_IRQENABLE
reg = MAILBOX_IRQENABLE(mdev->intr_type, usr);
reg = MAILBOX_IRQENABLE(mdev->intr_type, usr);
fifo->irqenable = MAILBOX_IRQENABLE(intr_type, tx_usr);
fifo->irqenable = MAILBOX_IRQENABLE(intr_type, rx_usr);