comconsole.c revision 119482 
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 119482 2003-08-25 23:28:32Z obrien $");
28
29#include <stand.h>
30#include <bootstrap.h>
31#include <machine/cpufunc.h>
32#include "libi386.h"
33
34/* selected defines from ns16550.h */
35#define	com_data	0	/* data register (R/W) */
36#define	com_dlbl	0	/* divisor latch low (W) */
37#define	com_dlbh	1	/* divisor latch high (W) */
38#define	com_ier		1	/* interrupt enable (W) */
39#define	com_iir		2	/* interrupt identification (R) */
40#define	com_fifo	2	/* FIFO control (W) */
41#define	com_lctl	3	/* line control register (R/W) */
42#define	com_cfcr	3	/* line control register (R/W) */
43#define	com_mcr		4	/* modem control register (R/W) */
44#define	com_lsr		5	/* line status register (R/W) */
45#define	com_msr		6	/* modem status register (R/W) */
46
47/* selected defines from sioreg.h */
48#define	CFCR_DLAB	0x80
49#define	MCR_RTS		0x02
50#define	MCR_DTR		0x01
51#define	LSR_TXRDY	0x20
52#define	LSR_RXRDY	0x01
53
54#define COMC_FMT	0x3		/* 8N1 */
55#define COMC_TXWAIT	0x40000		/* transmit timeout */
56#define COMC_BPS(x)	(115200 / (x))	/* speed to DLAB divisor */
57
58#ifndef	COMPORT
59#define COMPORT		0x3f8
60#endif
61#ifndef	COMSPEED
62#define COMSPEED	9600
63#endif
64
65static void	comc_probe(struct console *cp);
66static int	comc_init(int arg);
67static void	comc_putchar(int c);
68static int	comc_getchar(void);
69static int	comc_ischar(void);
70
71static int	comc_started;
72
73struct console comconsole = {
74    "comconsole",
75    "serial port",
76    0,
77    comc_probe,
78    comc_init,
79    comc_putchar,
80    comc_getchar,
81    comc_ischar
82};
83
84static void
85comc_probe(struct console *cp)
86{
87    /* XXX check the BIOS equipment list? */
88    cp->c_flags |= (C_PRESENTIN | C_PRESENTOUT);
89}
90
91static int
92comc_init(int arg)
93{
94    if (comc_started && arg == 0)
95	return 0;
96    comc_started = 1;
97
98    outb(COMPORT + com_cfcr, CFCR_DLAB | COMC_FMT);
99    outb(COMPORT + com_dlbl, COMC_BPS(COMSPEED) & 0xff);
100    outb(COMPORT + com_dlbh, COMC_BPS(COMSPEED) >> 8);
101    outb(COMPORT + com_cfcr, COMC_FMT);
102    outb(COMPORT + com_mcr, MCR_RTS | MCR_DTR);
103
104    do
105        inb(COMPORT + com_data);
106    while (inb(COMPORT + com_lsr) & LSR_RXRDY);
107
108    return(0);
109}
110
111static void
112comc_putchar(int c)
113{
114    int wait;
115
116    for (wait = COMC_TXWAIT; wait > 0; wait--)
117        if (inb(COMPORT + com_lsr) & LSR_TXRDY) {
118	    outb(COMPORT + com_data, (u_char)c);
119	    break;
120	}
121}
122
123static int
124comc_getchar(void)
125{
126    return(comc_ischar() ? inb(COMPORT + com_data) : -1);
127}
128
129static int
130comc_ischar(void)
131{
132    return(inb(COMPORT + com_lsr) & LSR_RXRDY);
133}
134