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ns16550.c revision 1.1 
      1 /*	$NetBSD: ns16550.c,v 1.1 2002/03/28 20:40:47 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2002 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Jason R. Thorpe for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed for the NetBSD Project by
     20  *	Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 /*
     39  * This file provides the cons_init() function and console I/O routines
     40  * for boards that use 16550-compatible UARTs.
     41  */
     42 
     43 #include <sys/types.h>
     44 #include <dev/ic/comreg.h>
     45 #include <lib/libsa/stand.h>
     46 
     47 #include "board.h"
     48 
     49 #define	INB(x)		*((__volatile uint8_t *) (CONADDR + (x)))
     50 #define	OUTB(x, v)	*((__volatile uint8_t *) (CONADDR + (x))) = (v)
     51 
     52 #define	ISSET(t,f)	((t) & (f))
     53 
     54 static int
     55 comspeed(int speed)
     56 {
     57 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
     58 
     59 	int x, err;
     60 
     61 	if (speed <= 0)
     62 		return (-1);
     63 	x = divrnd((COM_FREQ / 16), speed);
     64 	if (x <= 0)
     65 		return (-1);
     66 	err = divrnd((COM_FREQ / 16) * 1000, speed * x) - 1000;
     67 	if (err < 0)
     68 		err = -err;
     69 	if (err > COM_TOLERANCE)
     70 		return (-1);
     71 	return (x);
     72 #undef divrnd
     73 }
     74 
     75 void
     76 cons_init(void)
     77 {
     78 	int rate;
     79 
     80 	OUTB(com_cfcr, LCR_DLAB);
     81 	rate = comspeed(CONSPEED);
     82 	OUTB(com_dlbl, rate);
     83 	OUTB(com_dlbh, rate >> 8);
     84 	OUTB(com_cfcr, LCR_8BITS);
     85 	OUTB(com_mcr, MCR_DTR | MCR_RTS);
     86 	OUTB(com_fifo,
     87 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
     88 	OUTB(com_ier, 0);
     89 }
     90 
     91 int
     92 getchar(void)
     93 {
     94 	uint8_t stat;
     95 
     96 	while (!ISSET(stat = INB(com_lsr), LSR_RXRDY))
     97 		/* spin */ ;
     98 	return (INB(com_data));
     99 }
    100 
    101 static void
    102 iputchar(int c)
    103 {
    104 	uint8_t stat;
    105 	int timo;
    106 
    107 	/* Wait for any pending transmission to finish. */
    108 	timo = 50000;
    109 	while (!ISSET(stat = INB(com_lsr), LSR_TXRDY) && --timo)
    110 		/* spin */ ;
    111 
    112 	OUTB(com_data, c);
    113 
    114 	/* Wait for this transmission to complete. */
    115 	timo = 1500000;
    116 	while (!ISSET(stat = INB(com_lsr), LSR_TXRDY) && --timo)
    117 		/* spin */ ;
    118 
    119 	/* Clear any interrupts generated by this transmission. */
    120 	(void) INB(com_iir);
    121 }
    122 
    123 void
    124 putchar(int c)
    125 {
    126 
    127 	if (c == '\n')
    128 		iputchar('\r');
    129 	iputchar(c);
    130 }
    131