comconsole.c revision 120118 
1/*-
2 * Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
27__FBSDID("$FreeBSD: head/sys/boot/i386/libi386/comconsole.c 120118 2003-09-16 11:24:23Z bde $");
28
29#include <stand.h>
30#include <bootstrap.h>
31#include <machine/cpufunc.h>
32#include <dev/ic/ns16550.h>
33#include "libi386.h"
34
35#define COMC_FMT	0x3		/* 8N1 */
36#define COMC_TXWAIT	0x40000		/* transmit timeout */
37#define COMC_BPS(x)	(115200 / (x))	/* speed to DLAB divisor */
38
39#ifndef	COMPORT
40#define COMPORT		0x3f8
41#endif
42#ifndef	COMSPEED
43#define COMSPEED	9600
44#endif
45
46static void	comc_probe(struct console *cp);
47static int	comc_init(int arg);
48static void	comc_putchar(int c);
49static int	comc_getchar(void);
50static int	comc_ischar(void);
51
52static int	comc_started;
53
54struct console comconsole = {
55    "comconsole",
56    "serial port",
57    0,
58    comc_probe,
59    comc_init,
60    comc_putchar,
61    comc_getchar,
62    comc_ischar
63};
64
65static void
66comc_probe(struct console *cp)
67{
68    /* XXX check the BIOS equipment list? */
69    cp->c_flags |= (C_PRESENTIN | C_PRESENTOUT);
70}
71
72static int
73comc_init(int arg)
74{
75    if (comc_started && arg == 0)
76	return 0;
77    comc_started = 1;
78
79    outb(COMPORT + com_cfcr, CFCR_DLAB | COMC_FMT);
80    outb(COMPORT + com_dlbl, COMC_BPS(COMSPEED) & 0xff);
81    outb(COMPORT + com_dlbh, COMC_BPS(COMSPEED) >> 8);
82    outb(COMPORT + com_cfcr, COMC_FMT);
83    outb(COMPORT + com_mcr, MCR_RTS | MCR_DTR);
84
85    do
86        inb(COMPORT + com_data);
87    while (inb(COMPORT + com_lsr) & LSR_RXRDY);
88
89    return(0);
90}
91
92static void
93comc_putchar(int c)
94{
95    int wait;
96
97    for (wait = COMC_TXWAIT; wait > 0; wait--)
98        if (inb(COMPORT + com_lsr) & LSR_TXRDY) {
99	    outb(COMPORT + com_data, (u_char)c);
100	    break;
101	}
102}
103
104static int
105comc_getchar(void)
106{
107    return(comc_ischar() ? inb(COMPORT + com_data) : -1);
108}
109
110static int
111comc_ischar(void)
112{
113    return(inb(COMPORT + com_lsr) & LSR_RXRDY);
114}
115