kern_conf.c revision 47680 
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 1.41 1999/05/31 11:27:28 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	cdevsw[newentry->d_maj] = newentry;
116
117	if (newentry->d_bmaj >= 0 || newentry->d_bmaj < NUMCDEVSW)
118		bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
119
120	return 0;
121}
122
123int
124devsw_module_handler(module_t mod, int what, void* arg)
125{
126	struct devsw_module_data* data = (struct devsw_module_data*) arg;
127	int error;
128
129	if (data->cmaj == NOMAJ)
130		data->cdev = NODEV;
131	else
132		data->cdev = makedev(data->cmaj, 0);
133	switch (what) {
134	case MOD_LOAD:
135		error = cdevsw_add(data->cdevsw);
136		if (!error && data->cdevsw->d_strategy != nostrategy) {
137			if (data->bmaj == NOMAJ) {
138				data->bdev = data->cdev;
139				data->bmaj = data->cmaj;
140			} else {
141				data->bdev = makedev(data->bmaj, 0);
142			}
143			data->cdevsw->d_maj = data->bmaj;
144			bmaj2cmaj[major(data->bdev)] = major(data->cdev);
145		}
146		if (!error && data->chainevh)
147			error = data->chainevh(mod, what, data->chainarg);
148		return error;
149
150	case MOD_UNLOAD:
151		if (data->chainevh) {
152			error = data->chainevh(mod, what, data->chainarg);
153			if (error)
154				return error;
155		}
156		if (data->cdevsw->d_strategy != nostrategy)
157			bmaj2cmaj[major(data->bdev)] = 0;
158		return error;
159	}
160
161	if (data->chainevh)
162		return data->chainevh(mod, what, data->chainarg);
163	else
164		return 0;
165}
166
167/*
168 * dev_t and u_dev_t primitives
169 */
170
171#define DEVT_FASCIST 1
172
173int
174major(dev_t x)
175{
176	uintptr_t i = (uintptr_t)x;
177
178#ifdef DEVT_FASCIST
179	return(255 - ((i >> 8) & 0xff));
180#else
181	return((i >> 8) & 0xff);
182#endif
183}
184
185int
186minor(dev_t x)
187{
188	uintptr_t i = (uintptr_t)x;
189
190	return(i & 0xffff00ff);
191}
192
193dev_t
194makebdev(int x, int y)
195{
196	return (makedev(x, y));
197}
198
199dev_t
200makedev(int x, int y)
201{
202#ifdef DEVT_FASCIST
203        return ((dev_t) (((255 - x) << 8) | y));
204#else
205        return ((dev_t) ((x << 8) | y));
206#endif
207}
208
209udev_t
210dev2udev(dev_t x)
211{
212	return umakedev(major(x), minor(x));
213}
214
215dev_t
216udev2dev(udev_t x, int b)
217{
218	return makedev(umajor(x), uminor(x));
219}
220
221int
222uminor(udev_t dev)
223{
224	return(dev & 0xffff00ff);
225}
226
227int
228umajor(udev_t dev)
229{
230	return((dev & 0xff00) >> 8);
231}
232
233udev_t
234umakedev(int x, int y)
235{
236        return ((x << 8) | y);
237}
238
239