2 * Mach Operating System
3 * Copyright (c) 1992, 1991 Carnegie Mellon University
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
16 * Carnegie Mellon requests users of this software to return to
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
23 * any improvements or extensions that they make and grant Carnegie Mellon
24 * the rights to redistribute these changes.
26 * from: Mach, Revision 2.2 92/04/04 11:34:26 rpd
27 * $FreeBSD: src/sys/i386/boot/biosboot/serial.S,v 1.13 1999/08/28 00:43:14 peter Exp $
28 * $DragonFly: src/sys/platform/pc32/boot/biosboot/Attic/serial.S,v 1.2 2003/06/17 04:28:34 dillon Exp $
32 Copyright 1988, 1989, 1990, 1991, 1992
33 by Intel Corporation, Santa Clara, California.
37 Permission to use, copy, modify, and distribute this software and
38 its documentation for any purpose and without fee is hereby
39 granted, provided that the above copyright notice appears in all
40 copies and that both the copyright notice and this permission notice
41 appear in supporting documentation, and that the name of Intel
42 not be used in advertising or publicity pertaining to distribution
43 of the software without specific, written prior permission.
45 INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
46 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
47 IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
48 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
49 LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
50 NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
51 WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
55 * Serial bootblock interface routines
56 * Copyright (c) 1994, J"org Wunsch
58 * Permission to use, copy, modify and distribute this software and its
59 * documentation is hereby granted, provided that both the copyright
60 * notice and this permission notice appear in all copies of the
61 * software, derivative works or modified versions, and any portions
62 * thereof, and that both notices appear in supporting documentation.
64 * THE AUTHOR ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
65 * CONDITION. THE AUTHOR DISCLAIMS ANY LIABILITY OF ANY KIND FOR
66 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
71 #include <isa/sioreg.h>
77 * The serial port interface routines implement a simple polled i/o
78 * interface to a standard serial port. Due to the space restrictions
79 * for the boot blocks, no BIOS support is used (since BIOS requires
80 * expensive real/protected mode switches), instead the rudimentary
81 * BIOS support is duplicated here.
83 * The base address and speed for the i/o port are passed from the
84 * Makefile in the COMCONSOLE and CONSPEED preprocessor macros. The
85 * line control parameters are currently hard-coded to 8 bits, no
86 * parity, 1 stop bit (8N1). This can be changed in init_serial().
90 * void serial_putc(int ch);
91 * Write character `ch' to port COMCONSOLE.
94 movl $10000, %ecx # timeout
95 movl $COMCONSOLE + 5, %edx # line status reg
101 je 1b # TX buffer not empty
105 subl $5, %edx # TX output reg
106 outb %al, %dx # send this one
112 * int serial_getc(void);
113 * Read a character from port COMCONSOLE.
116 mov $COMCONSOLE + 5, %edx # line status reg
120 je 1b # no rx char available
123 subl $5, %edx # rx buffer reg
124 inb %dx, %al # fetch (first) character
126 andb $0x7F, %al # remove any parity bits we get
127 cmpb $0x7F, %al # make DEL...
129 movb $0x08, %al # look like BS
134 * int serial_ischar(void);
135 * If there is a character in the input buffer of port COMCONSOLE,
136 * return nonzero; otherwise return 0.
140 movl $COMCONSOLE + 5, %edx # line status reg
142 andb $0x01, %al # rx char available?
146 * void init_serial(void);
147 * Initialize port COMCONSOLE to speed CONSPEED, line settings 8N1.
150 movl $COMCONSOLE + 3, %edx # line control reg
152 outb %al, %dx # enable DLAB
154 subl $3, %edx # divisor latch, low byte
155 movb $COMBRD(CONSPEED) & 0xff, %al
157 incl %edx # divisor latch, high byte
158 movb $COMBRD(CONSPEED) >> 8, %al
161 incl %edx # fifo control register (if any)
163 outb %al, %dx # disable fifo to reduce worst-case busy-wait
165 incl %edx # line control reg
169 incl %edx # modem control reg
170 outb %al, %dx # enable DTR/RTS
172 /* Flush the input buffer. */
173 incl %edx # line status reg
175 subl $5, %edx # rx buffer reg
176 inb %dx, %al # throw away (unconditionally the first time)
177 addl $5, %edx # line status reg