sysdeps/standalone/m68k/m68020/mvme136/console.c

   1 /* Copyright (C) 1994, 1996 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Joel Sherrill (jsherril@redstone-emh2.army.mil),
   4    On-Line Applications Research Corporation.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <standalone.h>
  22 #include "m68020.h"
  23
  24 /* Console IO routines for a Motorola MVME135/MVME136 board.
  25
  26 They currently use the B port.  It should be possible to
  27 use the A port by filling in the reset of the chip structure,
  28 adding an ifdef for PORTA/PORTB, and switching the addresses,
  29 and maybe the macros based on the macro. */
  30
  31 /* M68681 DUART chip register structures and constants */
  32
  33 typedef struct {
  34   volatile unsigned char fill1[ 5 ];     /* channel A regs ( not used ) */
  35   volatile unsigned char isr;            /* interrupt status reg */
  36   volatile unsigned char fill2[ 2 ];     /* counter regs (not used) */
  37   volatile unsigned char mr1mr2b;        /* MR1B and MR2B regs */
  38   volatile unsigned char srb;            /* status reg channel B */
  39   volatile unsigned char fill3;          /* do not access */
  40   volatile unsigned char rbb;            /* receive buffer channel B */
  41   volatile unsigned char ivr;            /* interrupt vector register */
  42 } r_m681_info;
  43
  44 typedef struct {
  45   volatile unsigned char fill1[ 4 ];     /* channel A regs (not used) */
  46   volatile unsigned char acr;            /* auxillary control reg */
  47   volatile unsigned char imr;            /* interrupt mask reg */
  48   volatile unsigned char fill2[ 2 ];     /* counter regs (not used) */
  49   volatile unsigned char mr1mr2b;        /* MR1B and MR2B regs */
  50   volatile unsigned char csrb;           /* clock select reg */
  51   volatile unsigned char crb;            /* command reg */
  52   volatile unsigned char tbb;            /* transmit buffer channel B */
  53   volatile unsigned char ivr;            /* interrupt vector register */
  54 } w_m681_info;
  55
  56 #define RD_M68681     ((r_m681_info *)0xfffb0040)   /* ptr to the M68681 */
  57 #define WR_M68681     ((w_m681_info *)0xfffb0040)   /* ptr to the M68681 */
  58 #define RXRDYB        0x01               /* status reg recv ready mask */
  59 #define TXRDYB        0x04               /* status reg trans ready mask */
  60
  61 /* _Console_Putc
  62
  63 This routine transmits a character out the M68681.  It supports
  64 XON/XOFF flow control.  */
  65
  66 #define XON             0x11            /* control-Q */
  67 #define XOFF            0x13            /* control-S */
  68
  69 int
  70 _Console_Putc (ch)
  71      char ch;
  72 {
  73   while ( ! (RD_M68681->srb & TXRDYB) ) ;
  74   while ( RD_M68681->srb & RXRDYB )        /* must be an XOFF */
  75     if ( RD_M68681->rbb == XOFF )
  76       do {
  77         while ( ! (RD_M68681->srb & RXRDYB) ) ;
  78       } while ( RD_M68681->rbb != XON );
  79
  80   WR_M68681->tbb = ch;
  81   return( 0 );
  82 }
  83
  84 /* _Console_Getc
  85
  86 This routine reads a character from the UART and returns it. */
  87
  88 int
  89 _Console_Getc (poll)
  90      int poll;
  91 {
  92   if ( poll ) {
  93     if ( !(RD_M68681->srb & RXRDYB) )
  94       return -1;
  95     else
  96       return RD_M68681->rbb;
  97   } else {
  98     while ( !(RD_M68681->srb & RXRDYB) );
  99     return RD_M68681->rbb;
 100   }
 101 }