SUP_UART_ISC
isc = readl(port->membase + SUP_UART_ISC);
writel(isc, port->membase + SUP_UART_ISC);
isc = readl(port->membase + SUP_UART_ISC);
writel(isc, port->membase + SUP_UART_ISC);
isc = readl(port->membase + SUP_UART_ISC);
writel(isc, port->membase + SUP_UART_ISC);
isc = readl(port->membase + SUP_UART_ISC);
writel(isc, port->membase + SUP_UART_ISC);
writel(0, port->membase + SUP_UART_ISC); /* disable all interrupt */