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cninit.c revision 1.4 
      1 /*	$NetBSD: cninit.c,v 1.4 2001/11/13 05:32:50 lukem 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. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  * from: Utah $Hdr: cons.c 1.7 92/01/21$
     41  *
     42  *	@(#)cons.c	8.2 (Berkeley) 1/12/94
     43  */
     44 
     45 #include <sys/cdefs.h>
     46 __KERNEL_RCSID(0, "$NetBSD: cninit.c,v 1.4 2001/11/13 05:32:50 lukem Exp $");
     47 
     48 #include <sys/param.h>
     49 #include <sys/proc.h>
     50 #include <sys/user.h>
     51 #include <sys/systm.h>
     52 #include <sys/buf.h>
     53 #include <sys/ioctl.h>
     54 #include <sys/tty.h>
     55 #include <sys/file.h>
     56 #include <sys/conf.h>
     57 #include <sys/vnode.h>
     58 
     59 #include <dev/cons.h>
     60 
     61 extern struct consdev constab[];
     62 
     63 extern struct	consdev *cn_tab;	/* physical console device info */
     64 
     65 void
     66 cninit()
     67 {
     68 	struct consdev *cp;
     69 	struct consdev *bestMatch;
     70 
     71 	bestMatch = cn_tab = NULL;
     72 	/*
     73 	 * Collect information about all possible consoles
     74 	 * and find the one with highest priority
     75 	 */
     76 	for (cp = constab; cp->cn_probe; cp++) {
     77 		(*cp->cn_probe)(cp);
     78 		if (cp->cn_pri > CN_DEAD &&
     79 		    (bestMatch == NULL || cp->cn_pri > bestMatch->cn_pri)) {
     80 			bestMatch = cp;
     81 		}
     82 	}
     83 	/*
     84 	 * No console, we can handle it
     85 	 */
     86 	if ((cp = bestMatch) == NULL)
     87 		return;
     88 	/*
     89 	 * Turn on console
     90 	 */
     91 	{
     92 		struct consdev *old_cn_tab = cn_tab;
     93 
     94  		(*cp->cn_init)(cp);
     95 		/*
     96 		 * Now let everyone know we have an active console they can
     97 		 * use for diagnostics. If we use cn_tab in the search loop
     98 		 * then interrupts from the ethernet at boot may cause system
     99 		 * hang.
    100 		 */
    101 		if (cn_tab == old_cn_tab)
    102 			cn_tab = bestMatch;
    103 	}
    104 }
    105