xref: /illumos-gate/usr/src/uts/sun4/os/bus_func.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/conf.h>
30 #include <sys/sysmacros.h>
31 #include <sys/async.h>
32 
33 static bus_func_desc_t *bfd_list = NULL; /* list of busfunc descriptors */
34 kmutex_t bfd_lock;		/* lock protecting bfd_list */
35 
36 /*
37  * Register a new bus function.  We expect this function to be called from a
38  * driver attach or detach routine, so we can safely perform a sleeping
39  * allocation here.  We just insert the new element at the head of the list.
40  * For more information on bus_func semantics, refer to sun4u/sys/async.h.
41  */
42 void
43 bus_func_register(int type, busfunc_t func, void *arg)
44 {
45 	bus_func_desc_t *bfd = kmem_alloc(sizeof (bus_func_desc_t), KM_SLEEP);
46 
47 	bfd->bf_type = type;
48 	bfd->bf_func = func;
49 	bfd->bf_arg = arg;
50 
51 	mutex_enter(&bfd_lock);
52 	bfd->bf_next = bfd_list;
53 	bfd_list = bfd;
54 	mutex_exit(&bfd_lock);
55 }
56 
57 /*
58  * Unregister the specified bus function.  We only delete an element that
59  * exactly matches the specified (type, func, arg) tuple.  We expect this
60  * function to only be called from driver detach context.
61  */
62 void
63 bus_func_unregister(int type, busfunc_t func, void *arg)
64 {
65 	bus_func_desc_t *bfd, **pp;
66 
67 	mutex_enter(&bfd_lock);
68 	pp = &bfd_list;
69 
70 	for (bfd = bfd_list; bfd != NULL; bfd = bfd->bf_next) {
71 		if (bfd->bf_type == type && bfd->bf_func == func &&
72 		    bfd->bf_arg == arg) {
73 			*pp = bfd->bf_next;
74 			break;
75 		}
76 		pp = &bfd->bf_next;
77 	}
78 
79 	mutex_exit(&bfd_lock);
80 
81 	if (bfd != NULL)
82 		kmem_free(bfd, sizeof (bus_func_desc_t));
83 }
84 
85 /*
86  * Invoke the registered bus functions of the specified type.  We return the
87  * maximum of the result values (e.g. BF_FATAL if any call returned BF_FATAL).
88  * This function assumes that (1) the BF_* constants are defined so that the
89  * most fatal error has the highest numerical value, and (2) that the bf_func
90  * callbacks obey the rules described in async.h.
91  */
92 uint_t
93 bus_func_invoke(int type)
94 {
95 	bus_func_desc_t *bfd;
96 	uint_t err = BF_NONE;
97 
98 	mutex_enter(&bfd_lock);
99 
100 	for (bfd = bfd_list; bfd != NULL; bfd = bfd->bf_next) {
101 		if (bfd->bf_type == type) {
102 			uint_t status = bfd->bf_func(bfd->bf_arg);
103 			err = MAX(err, status);
104 		}
105 	}
106 
107 	mutex_exit(&bfd_lock);
108 	return (err);
109 }
110