AML_UART_TX_FULL
while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
while (readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)