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/boot/pc98/boot2/serial_16550.S,v 1.1.2.2 2002/03/08 13:00:22 nyan Exp $
31 Copyright 1988, 1989, 1990, 1991, 1992
32 by Intel Corporation, Santa Clara, California.
36 Permission to use, copy, modify, and distribute this software and
37 its documentation for any purpose and without fee is hereby
38 granted, provided that the above copyright notice appears in all
39 copies and that both the copyright notice and this permission notice
40 appear in supporting documentation, and that the name of Intel
41 not be used in advertising or publicity pertaining to distribution
42 of the software without specific, written prior permission.
44 INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
45 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
46 IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
47 CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
48 LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
49 NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
50 WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
54 * Serial bootblock interface routines
55 * Copyright (c) 1994, J"org Wunsch
57 * Permission to use, copy, modify and distribute this software and its
58 * documentation is hereby granted, provided that both the copyright
59 * notice and this permission notice appear in all copies of the
60 * software, derivative works or modified versions, and any portions
61 * thereof, and that both notices appear in supporting documentation.
63 * THE AUTHOR ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
64 * CONDITION. THE AUTHOR DISCLAIMS ANY LIABILITY OF ANY KIND FOR
65 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
70 #include <isa/sioreg.h>
76 * The serial port interface routines implement a simple polled i/o
77 * interface to a standard serial port. Due to the space restrictions
78 * for the boot blocks, no BIOS support is used (since BIOS requires
79 * expensive real/protected mode switches), instead the rudimentary
80 * BIOS support is duplicated here.
82 * The base address and speed for the i/o port are passed from the
83 * Makefile in the COMCONSOLE and CONSPEED preprocessor macros. The
84 * line control parameters are currently hard-coded to 8 bits, no
85 * parity, 1 stop bit (8N1). This can be changed in init_serial().
89 * void serial_putc(int ch);
90 * Write character `ch' to port COMCONSOLE.
93 movl $10000, %ecx # timeout
94 movl $COMCONSOLE + 5, %edx # line status reg
100 je 1b # TX buffer not empty
104 subl $5, %edx # TX output reg
105 outb %al, %dx # send this one
111 * int serial_getc(void);
112 * Read a character from port COMCONSOLE.
115 mov $COMCONSOLE + 5, %edx # line status reg
119 je 1b # no rx char available
122 subl $5, %edx # rx buffer reg
123 inb %dx, %al # fetch (first) character
125 andb $0x7F, %al # remove any parity bits we get
126 cmpb $0x7F, %al # make DEL...
128 movb $0x08, %al # look like BS
133 * int serial_ischar(void);
134 * If there is a character in the input buffer of port COMCONSOLE,
135 * return nonzero; otherwise return 0.
139 movl $COMCONSOLE + 5, %edx # line status reg
141 andb $0x01, %al # rx char available?
145 * void init_serial(void);
146 * Initialize port COMCONSOLE to speed CONSPEED, line settings 8N1.
149 movl $COMCONSOLE + 3, %edx # line control reg
151 outb %al, %dx # enable DLAB
153 subl $3, %edx # divisor latch, low byte
154 movb (1843200 / (16*(CONSPEED))) & 0xff, %al
156 incl %edx # divisor latch, high byte
157 movb (1843200 / (16*(CONSPEED))) >> 8, %al
160 incl %edx # fifo control register (if any)
162 outb %al, %dx # disable fifo to reduce worst-case busy-wait
164 incl %edx # line control reg
168 incl %edx # modem control reg
169 outb %al, %dx # enable DTR/RTS
171 /* Flush the input buffer. */
172 incl %edx # line status reg
174 subl $5, %edx # rx buffer reg
175 inb %dx, %al # throw away (unconditionally the first time)
176 addl $5, %edx # line status reg