uart.c

   1 /*****************************************************************************
   2
   3        Copyright © 1995, 1996 Digital Equipment Corporation,
   4                        Maynard, Massachusetts.
   5
   6                         All Rights Reserved
   7
   8 Permission to use, copy, modify, and distribute this software and its
   9 documentation for any purpose and without fee is hereby granted, provided
  10 that the copyright notice and this permission notice appear in all copies
  11 of software and supporting documentation, and that the name of Digital not
  12 be used in advertising or publicity pertaining to distribution of the software
  13 without specific, written prior permission. Digital grants this permission
  14 provided that you prominently mark, as not part of the original, any
  15 modifications made to this software or documentation.
  16
  17 Digital Equipment Corporation disclaims all warranties and/or guarantees
  18 with regard to this software, including all implied warranties of fitness for
  19 a particular purpose and merchantability, and makes no representations
  20 regarding the use of, or the results of the use of, the software and
  21 documentation in terms of correctness, accuracy, reliability, currentness or
  22 otherwise; and you rely on the software, documentation and results solely at
  23 your own risk.
  24
  25 ******************************************************************************/
  26
  27 /*
  28  * david.rusling@reo.mts.dec.com
  29  *
  30  * Modified for QEMU PALcode by rth@twiddle.net.
  31  */
  32
  33 #include "protos.h"
  34 #include "uart.h"
  35
  36 #ifndef SERIAL_SPEED
  37 #define SERIAL_SPEED 9600
  38 #endif
  39
  40 int
  41 uart_charav(int offset)
  42 {
  43         return inb(com2Lsr + offset) & 1;
  44 }
  45
  46 int
  47 uart_getchar(int offset)
  48 {
  49         /* If interrupts are enabled, use wtint assuming that either the
  50            device itself will wake us, or that a clock interrupt will.  */
  51         if ((rdps() & 7) == 0) {
  52             while (!uart_charav(offset)) {
  53                 wtint(0);
  54             }
  55         } else {
  56             while (!uart_charav(offset))
  57                 continue;
  58         }
  59
  60         return inb(com2Rbr + offset);
  61 }
  62
  63 void
  64 uart_putchar_raw(int offset, char c)
  65 {
  66         while ((inb(com2Lsr + offset) & 0x20) == 0)
  67                 continue;
  68         outb(c, com2Thr + offset);
  69 }
  70
  71 void
  72 uart_putchar(int offset, char c)
  73 {
  74         if (c == '\n')
  75                 uart_putchar_raw(offset, '\r');
  76         uart_putchar_raw(offset, c);
  77 }
  78
  79 void
  80 uart_puts(int offset, const char *s)
  81 {
  82         while (*s != '\0')
  83                 uart_putchar(offset, *s++);
  84 }
  85
  86 void
  87 uart_init_line(int offset, int baud)
  88 {
  89         int i;
  90         int baudconst;
  91
  92         switch (baud) {
  93         case 56000:
  94                 baudconst = 2;
  95                 break;
  96         case 38400:
  97                 baudconst = 3;
  98                 break;
  99         case 19200:
 100                 baudconst = 6;
 101                 break;
 102         case 9600:
 103                 baudconst = 12;
 104                 break;
 105         case 4800:
 106                 baudconst = 24;
 107                 break;
 108         case 2400:
 109                 baudconst = 48;
 110                 break;
 111         case 1200:
 112                 baudconst = 96;
 113                 break;
 114         case 300:
 115                 baudconst = 384;
 116                 break;
 117         case 150:
 118                 baudconst = 768;
 119                 break;
 120         default:
 121                 baudconst = 12;
 122                 break;
 123         }
 124
 125
 126         outb(0x87, com2Lcr + offset);
 127         outb(0, com2Dlm + offset);
 128         outb(baudconst, com2Dll + offset);
 129         outb(0x07, com2Lcr + offset);
 130         outb(0x0F, com2Mcr + offset);
 131
 132         for (i = 10; i > 0; i--) {
 133                 if (inb(com2Lsr + offset) == 0)
 134                         break;
 135                 inb(com2Rbr + offset);
 136         }
 137 }
 138
 139 void uart_init(void)
 140 {
 141         uart_init_line(COM1, SERIAL_SPEED);
 142         uart_init_line(COM2, SERIAL_SPEED);
 143 }