M_CAN_IR
m_can_write(cdev, M_CAN_IR, IR_MRAF);
irqstatus = cdev->irqstatus | m_can_read(cdev, M_CAN_IR);
while ((ir_read = m_can_read(cdev, M_CAN_IR)) != 0) {
m_can_write(cdev, M_CAN_IR, ir);