kern_conf.c revision 48859 
1/*-
2 * Parts Copyright (c) 1995 Terrence R. Lambert
3 * Copyright (c) 1995 Julian R. Elischer
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *      This product includes software developed by Terrence R. Lambert.
17 * 4. The name Terrence R. Lambert may not be used to endorse or promote
18 *    products derived from this software without specific prior written
19 *    permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $Id: kern_conf.c,v 1.47 1999/07/04 14:58:38 phk Exp $
34 */
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/module.h>
39#include <sys/conf.h>
40#include <sys/vnode.h>
41
42#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
43
44struct cdevsw 	*cdevsw[NUMCDEVSW];
45
46int	bmaj2cmaj[NUMCDEVSW];
47
48/*
49 * Routine to convert from character to block device number.
50 *
51 * A minimal stub routine can always return NODEV.
52 */
53dev_t
54chrtoblk(dev_t dev)
55{
56	struct cdevsw *cd;
57
58	if((cd = devsw(dev)) != NULL) {
59          if (cd->d_bmaj != -1)
60	    return(makedev(cd->d_bmaj,minor(dev)));
61	}
62	return(NODEV);
63}
64
65struct cdevsw *
66devsw(dev_t dev)
67{
68        return(cdevsw[major(dev)]);
69}
70
71struct cdevsw *
72bdevsw(dev_t dev)
73{
74        struct cdevsw *c;
75        int i = major(dev);
76
77        if (bmaj2cmaj[i] == 254)
78                return 0;
79
80        c = cdevsw[bmaj2cmaj[major(dev)]];
81        if (!c) {
82                printf("bogus bdev dev_t %p, no cdev\n", (void *)dev);
83                Debugger("Bummer");
84                return 0;
85        }
86        /* CMAJ zero is the console, which has no strategy so this works */
87        if (c->d_strategy)
88                return (c);
89        return (0);
90}
91
92/*
93 *  Add a cdevsw entry
94 */
95
96int
97cdevsw_add(struct cdevsw *newentry)
98{
99	int i;
100	static int setup;
101
102	if (!setup) {
103		for (i = 0; i < NUMCDEVSW; i++)
104			if (!bmaj2cmaj[i])
105				bmaj2cmaj[i] = 254;
106		setup++;
107	}
108
109	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
110		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
111		    newentry->d_name, newentry->d_maj);
112		return EINVAL;
113	}
114
115	if (cdevsw[newentry->d_maj]) {
116		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
117		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
118	}
119	cdevsw[newentry->d_maj] = newentry;
120
121	if (newentry->d_bmaj >= 0 && newentry->d_bmaj < NUMCDEVSW) {
122		if (bmaj2cmaj[newentry->d_bmaj] != 254) {
123			printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n",
124			    newentry->d_name,
125			    cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name);
126		}
127		bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
128	}
129
130	return 0;
131}
132
133/*
134 *  Remove a cdevsw entry
135 */
136
137int
138cdevsw_remove(struct cdevsw *oldentry)
139{
140	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
141		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
142		    oldentry->d_name, oldentry->d_maj);
143		return EINVAL;
144	}
145
146	cdevsw[oldentry->d_maj] = NULL;
147
148	if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW)
149		bmaj2cmaj[oldentry->d_bmaj] = NULL;
150
151	return 0;
152}
153
154int
155devsw_module_handler(module_t mod, int what, void* arg)
156{
157	struct devsw_module_data* data = (struct devsw_module_data*) arg;
158	int error = 0;
159
160	switch (what) {
161	case MOD_LOAD:
162		error = cdevsw_add(data->cdevsw);
163		if (!error && data->chainevh)
164			error = data->chainevh(mod, what, data->chainarg);
165		return error;
166
167	case MOD_UNLOAD:
168		if (data->chainevh) {
169			error = data->chainevh(mod, what, data->chainarg);
170			if (error)
171				return error;
172		}
173		cdevsw_remove(data->cdevsw);
174		return error;
175	}
176
177	if (data->chainevh)
178		return data->chainevh(mod, what, data->chainarg);
179	else
180		return 0;
181}
182
183/*
184 * dev_t and u_dev_t primitives
185 */
186
187#define DEVT_FASCIST 1
188
189int
190major(dev_t x)
191{
192	uintptr_t i = (uintptr_t)x;
193
194#ifdef DEVT_FASCIST
195	return(255 - ((i >> 8) & 0xff));
196#else
197	return((i >> 8) & 0xff);
198#endif
199}
200
201int
202minor(dev_t x)
203{
204	uintptr_t i = (uintptr_t)x;
205
206	return(i & 0xffff00ff);
207}
208
209dev_t
210makebdev(int x, int y)
211{
212	return (makedev(x, y));
213}
214
215dev_t
216makedev(int x, int y)
217{
218#ifdef DEVT_FASCIST
219        return ((dev_t)(uintptr_t) (((255 - x) << 8) | y));
220#else
221        return ((dev_t)(uintptr_t) ((x << 8) | y));
222#endif
223}
224
225udev_t
226dev2udev(dev_t x)
227{
228	return makeudev(major(x), minor(x));
229}
230
231dev_t
232udev2dev(udev_t x, int b)
233{
234	return makedev(umajor(x), uminor(x));
235}
236
237int
238uminor(udev_t dev)
239{
240	return(dev & 0xffff00ff);
241}
242
243int
244umajor(udev_t dev)
245{
246	return((dev & 0xff00) >> 8);
247}
248
249udev_t
250makeudev(int x, int y)
251{
252        return ((x << 8) | y);
253}
254
255