1 /* $NetBSD: cninit.c,v 1.14 2020/07/29 01:55:58 uwe Exp $ */
2
3 /*
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: Utah $Hdr: cons.c 1.7 92/01/21$
37 *
38 * @(#)cons.c 8.2 (Berkeley) 1/12/94
39 */
40
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: cninit.c,v 1.14 2020/07/29 01:55:58 uwe Exp $");
43
44 #include <sys/param.h>
45 #include <sys/proc.h>
46 #include <sys/systm.h>
47 #include <sys/buf.h>
48 #include <sys/ioctl.h>
49 #include <sys/tty.h>
50 #include <sys/file.h>
51 #include <sys/conf.h>
52 #include <sys/vnode.h>
53
54 #include <dev/cons.h>
55
56 void
cninit(void)57 cninit(void)
58 {
59 struct consdev *bestMatch;
60 struct consdev *cp;
61
62 /*
63 * Collect information about all possible consoles
64 * and find the one with highest priority
65 */
66 bestMatch = NULL;
67 for (cp = constab; cp->cn_probe; cp++) {
68 (*cp->cn_probe)(cp);
69 if (cp->cn_pri > CN_DEAD &&
70 (bestMatch == NULL || cp->cn_pri > bestMatch->cn_pri)) {
71 bestMatch = cp;
72 }
73 }
74
75 /*
76 * No console, we can handle it
77 */
78 if (bestMatch == NULL)
79 return;
80
81 /*
82 * Turn on console
83 */
84 {
85 struct consdev *old_cn_tab = cn_tab;
86
87 /* cn_init may set cn_tab to self */
88 (*bestMatch->cn_init)(bestMatch);
89
90 /*
91 * Now let everyone know we have an active console they can
92 * use for diagnostics. If we use cn_tab in the search loop
93 * then interrupts from the ethernet at boot may cause system
94 * hang.
95 */
96 if (cn_tab == old_cn_tab) /* if cn_init didn't, set it */
97 cn_tab = bestMatch;
98 }
99 }
100