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ns16550.c revision 1.2 
      1 /*	$NetBSD: ns16550.c,v 1.2 2003/03/25 23:32:41 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 #ifndef NS16550_FREQ
     55 #define	NS16550_FREQ	COM_FREQ
     56 #endif
     57 
     58 static int
     59 comspeed(int speed)
     60 {
     61 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
     62 
     63 	int x, err;
     64 
     65 	if (speed <= 0)
     66 		return (-1);
     67 	x = divrnd((NS16550_FREQ / 16), speed);
     68 	if (x <= 0)
     69 		return (-1);
     70 	err = divrnd((((quad_t)NS16550_FREQ) / 16) * 1000, speed * x) - 1000;
     71 	if (err < 0)
     72 		err = -err;
     73 	if (err > COM_TOLERANCE)
     74 		return (-1);
     75 	return (x);
     76 #undef divrnd
     77 }
     78 
     79 void
     80 cons_init(void)
     81 {
     82 	int rate;
     83 
     84 	OUTB(com_cfcr, LCR_DLAB);
     85 	rate = comspeed(CONSPEED);
     86 	OUTB(com_dlbl, rate);
     87 	OUTB(com_dlbh, rate >> 8);
     88 	OUTB(com_cfcr, LCR_8BITS);
     89 	OUTB(com_mcr, MCR_DTR | MCR_RTS);
     90 	OUTB(com_fifo,
     91 	    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
     92 	OUTB(com_ier, 0);
     93 }
     94 
     95 int
     96 getchar(void)
     97 {
     98 	uint8_t stat;
     99 
    100 	while (!ISSET(stat = INB(com_lsr), LSR_RXRDY))
    101 		/* spin */ ;
    102 	return (INB(com_data));
    103 }
    104 
    105 static void
    106 iputchar(int c)
    107 {
    108 	uint8_t stat;
    109 	int timo;
    110 
    111 	/* Wait for any pending transmission to finish. */
    112 	timo = 50000;
    113 	while (!ISSET(stat = INB(com_lsr), LSR_TXRDY) && --timo)
    114 		/* spin */ ;
    115 
    116 	OUTB(com_data, c);
    117 
    118 	/* Wait for this transmission to complete. */
    119 	timo = 1500000;
    120 	while (!ISSET(stat = INB(com_lsr), LSR_TXRDY) && --timo)
    121 		/* spin */ ;
    122 
    123 	/* Clear any interrupts generated by this transmission. */
    124 	(void) INB(com_iir);
    125 }
    126 
    127 void
    128 putchar(int c)
    129 {
    130 
    131 	if (c == '\n')
    132 		iputchar('\r');
    133 	iputchar(c);
    134 }
    135