freebsd-dev/sys/boot/i386/libi386/vidconsole.c

/*
 * Copyright (c) 1998 Michael Smith (msmith@freebsd.org)
 * Copyright (c) 1997 Kazutaka YOKOTA (yokota@zodiac.mech.utsunomiya-u.ac.jp)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * 	From Id: probe_keyboard.c,v 1.13 1997/06/09 05:10:55 bde Exp
 *
 *	$Id: vidconsole.c,v 1.2 1998/09/17 23:52:10 msmith Exp $
 */

#include <stand.h>
#include <bootstrap.h>
#include <btxv86.h>
#include "libi386.h"

#if KEYBOARD_PROBE
#include <machine/cpufunc.h>

static int	probe_keyboard(void);
#endif
static void	vidc_probe(struct console *cp);
static int	vidc_init(int arg);
static void	vidc_putchar(int c);
static int	vidc_getchar(void);
static int	vidc_ischar(void);

struct console vidconsole = {
    "vidconsole",
    "internal video/keyboard",
    0,
    vidc_probe,
    vidc_init,
    vidc_putchar,
    vidc_getchar,
    vidc_ischar
};

static void
vidc_probe(struct console *cp)
{
    
    /* look for a keyboard */
#if KEYBOARD_PROBE
    if (probe_keyboard())
#endif
    {
	
	cp->c_flags |= C_PRESENTIN;
    }

    /* XXX for now, always assume we can do BIOS screen output */
    cp->c_flags |= C_PRESENTOUT;
}

static int
vidc_init(int arg)
{
    return(0);	/* XXX reinit? */
}

static void
vidc_putchar(int c)
{
    v86.ctl = 0;
    v86.addr = 0x10;
    v86.eax = 0xe00 | c;
    v86.ebx = 0x7;
    v86int();
}

static int
vidc_getchar(void)
{
    if (vidc_ischar()) {
	v86.ctl = 0;
	v86.addr = 0x16;
	v86.eax = 0x0;
	v86int();
	return(v86.eax & 0xff);
    } else {
	return(-1);
    }
}

static int
vidc_ischar(void)
{
    v86.ctl = 0;
    v86.addr = 0x16;
    v86.eax = 0x100;
    v86int();
    return(v86.eax);
}

#if KEYBOARD_PROBE

#define PROBE_MAXRETRY	5
#define PROBE_MAXWAIT	400
#define IO_DUMMY	0x84
#define IO_KBD		0x060		/* 8042 Keyboard */

/* selected defines from kbdio.h */
#define KBD_STATUS_PORT 	4	/* status port, read */
#define KBD_DATA_PORT		0	/* data port, read/write 
					 * also used as keyboard command
					 * and mouse command port 
					 */
#define KBDC_ECHO		0x00ee
#define KBDS_ANY_BUFFER_FULL	0x0001
#define KBDS_INPUT_BUFFER_FULL	0x0002
#define KBD_ECHO		0x00ee

/* 7 microsec delay necessary for some keyboard controllers */
static void
delay7(void)
{
    /* 
     * I know this is broken, but no timer is avaiable yet at this stage...
     * See also comments in `delay1ms()'.
     */
    inb(IO_DUMMY); inb(IO_DUMMY);
    inb(IO_DUMMY); inb(IO_DUMMY);
    inb(IO_DUMMY); inb(IO_DUMMY);
}

/*
 * This routine uses an inb to an unused port, the time to execute that
 * inb is approximately 1.25uS.  This value is pretty constant across
 * all CPU's and all buses, with the exception of some PCI implentations
 * that do not forward this I/O adress to the ISA bus as they know it
 * is not a valid ISA bus address, those machines execute this inb in
 * 60 nS :-(.
 *
 */
static void
delay1ms(void)
{
    int i = 800;
    while (--i >= 0)
	(void)inb(0x84);
}

/* 
 * We use the presence/absence of a keyboard to determine whether the internal
 * console can be used for input.
 *
 * Perform a simple test on the keyboard; issue the ECHO command and see
 * if the right answer is returned. We don't do anything as drastic as
 * full keyboard reset; it will be too troublesome and take too much time.
 */
static int
probe_keyboard(void)
{
    int retry = PROBE_MAXRETRY;
    int wait;
    int i;

    while (--retry >= 0) {
	/* flush any noise */
	while (inb(IO_KBD + KBD_STATUS_PORT) & KBDS_ANY_BUFFER_FULL) {
	    delay7();
	    inb(IO_KBD + KBD_DATA_PORT);
	    delay1ms();
	}

	/* wait until the controller can accept a command */
	for (wait = PROBE_MAXWAIT; wait > 0; --wait) {
	    if (((i = inb(IO_KBD + KBD_STATUS_PORT)) 
                & (KBDS_INPUT_BUFFER_FULL | KBDS_ANY_BUFFER_FULL)) == 0)
		break;
	    if (i & KBDS_ANY_BUFFER_FULL) {
		delay7();
	        inb(IO_KBD + KBD_DATA_PORT);
	    }
	    delay1ms();
	}
	if (wait <= 0)
	    continue;

	/* send the ECHO command */
	outb(IO_KBD + KBD_DATA_PORT, KBDC_ECHO);

	/* wait for a response */
	for (wait = PROBE_MAXWAIT; wait > 0; --wait) {
	     if (inb(IO_KBD + KBD_STATUS_PORT) & KBDS_ANY_BUFFER_FULL)
		 break;
	     delay1ms();
	}
	if (wait <= 0)
	    continue;

	delay7();
	i = inb(IO_KBD + KBD_DATA_PORT);
#ifdef PROBE_KBD_BEBUG
        printf("probe_keyboard: got 0x%x.\n", i);
#endif
	if (i == KBD_ECHO) {
	    /* got the right answer */
	    return (0);
	}
    }

    return (1);
}
#endif /* KEYBOARD_PROBE */