static unsigned char uart8250_rx_byte(unsigned base_port) { unsigned long int i = SINGLE_CHAR_TIMEOUT; while (i-- && !uart8250_can_rx_byte(base_port)); if (i) return inb(base_port + UART8250_RBR); else return 0x0; }
static int ttyS0_tst_byte(void) { return uart8250_can_rx_byte(CONFIG_TTYS0_BASE); }