UART_TX_BUSY
while ((bus_space_read_4(iot, ioh, UART_FLAGS) & UART_TX_BUSY) && --timo)
if (bus_space_read_4(iot, ioh, UART_FLAGS) & UART_TX_BUSY) {
while ((bus_space_read_4(iot, ioh, UART_FLAGS) & UART_TX_BUSY) && --timo)
while ((bus_space_read_4(iot, ioh, UART_FLAGS) & UART_TX_BUSY) && --timo)
while ((bus_space_read_4(iot, ioh, UART_FLAGS) & UART_TX_BUSY) && --timo)