freebsd-dev/sys/i386/boot/biosboot/probe_keyboard.c
Bill Paul f778c9da00 Submitted by: Bill Paul (wpaul@ctr.columbia.edu)
Obtained from:
bios boot block changed to allow booting from both the attached graphics
display and from a serial port. (A specially compiled serial boot block
is no longer necessary.) The boot block should detect the presence or
absence of a keyboard: if there is no keyboard, COM1 is turned into the
console. This simulates the behavior of the Sun boot PROMs. Unplug your
keyboard, attach a terminal to COM1 and you should be ready to go. :)
1995-01-20 07:48:27 +00:00

83 lines
2.9 KiB
C

/*-
* Copyright (c) 1992-1995 Søren Schmidt
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz and Don Ahn.
*
* 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
* in this position and unchanged.
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* This is a modified version of the keyboard reset code used in syscons.
* If the keyboard reset fails, we assume that the keyboard has been
* unplugged and we use a serial port (COM1) as the console instead.
* Returns 1 on failure (no keyboard), 0 on success (keyboard attached).
*
* This grody hack brought to you by Bill Paul (wpaul@ctr.columbia.edu)
*
* $Id$
*/
#include <machine/console.h>
#include <machine/cpufunc.h>
#ifdef BOOTWAIT
extern int delay1ms(void);
#else
int delay1ms()
{
int i = 800;
while (--i >= 0)
(void)inb(0x84);
}
#endif
int
probe_keyboard(void)
{
int i, retries = 5;
unsigned char val;
/* Try to reset keyboard hardware */
while (retries--) {
outb(KB_DATA, KB_RESET);
for (i=0; i<100000; i++) {
delay1ms();
val = inb(KB_DATA);
if (val == KB_ACK || val == KB_ECHO)
return(0);
if (val == KB_RESEND)
return (1);
}
}
return (0);
}