arch/ppc/boot/ns16550.c

   1 /*
   2  * COM1 NS16550 support
   3  */
   4
   5 #include "ns16550.h"
   6 typedef struct NS16550 *NS16550_t;
   7
   8 const NS16550_t COM_PORTS[] = { (NS16550_t) COM1,
   9     (NS16550_t) COM2,
  10     (NS16550_t) COM3,
  11     (NS16550_t) COM4 };
  12
  13 volatile struct NS16550 *
  14 NS16550_init(int chan)
  15 {
  16  volatile struct NS16550 *com_port;
  17  volatile unsigned char xx;
  18  com_port = (struct NS16550 *) COM_PORTS[chan];
  19  /* See if port is present */
  20  com_port->lcr = 0x00;
  21  com_port->ier = 0xFF;
  22 #if 0
  23  if (com_port->ier != 0x0F) return ((struct NS16550 *)0);
  24 #endif
  25  com_port->ier = 0x00;
  26  com_port->lcr = 0x80;  /* Access baud rate */
  27  com_port->dll = 0xc;  /* 9600 baud */
  28  com_port->dlm = 0xc >> 8;
  29  com_port->lcr = 0x03;  /* 8 data, 1 stop, no parity */
  30  com_port->mcr = 0x03;  /* RTS/DTR */
  31  com_port->fcr = 0x07;  /* Clear & enable FIFOs */
  32  return (com_port);
  33 }
  34
  35
  36 NS16550_putc(volatile struct NS16550 *com_port, unsigned char c)
  37 {
  38  volatile int i;
  39  while ((com_port->lsr & LSR_THRE) == 0) ;
  40  com_port->thr = c;
  41 }
  42
  43 unsigned char
  44 NS16550_getc(volatile struct NS16550 *com_port)
  45 {
  46  while ((com_port->lsr & LSR_DR) == 0) ;
  47  return (com_port->rbr);
  48 }
  49
  50 NS16550_tstc(volatile struct NS16550 *com_port)
  51 {
  52  return ((com_port->lsr & LSR_DR) != 0);
  53 }
  54
  55
  56