kern_conf.c revision 47069 
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 1.38 1999/05/12 11:06:45 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 NUMCDEV 256
43#define cdevsw_ALLOCSTART	(NUMCDEV/2)
44
45struct cdevsw 	*cdevsw[NUMCDEV];
46int	nchrdev = NUMCDEV;
47
48int	bmaj2cmaj[NUMCDEV];
49int	nblkdev = NUMCDEV;
50
51/*
52 * Routine to convert from character to block device number.
53 *
54 * A minimal stub routine can always return NODEV.
55 */
56dev_t
57chrtoblk(dev_t dev)
58{
59	struct cdevsw *cd;
60
61	if((cd = devsw(dev)) != NULL) {
62          if (cd->d_bmaj != -1)
63	    return(makedev(cd->d_bmaj,minor(dev)));
64	}
65	return(NODEV);
66}
67
68int
69cdevsw_add(dev_t *descrip,
70		struct cdevsw *newentry,
71		struct cdevsw **oldentry)
72{
73	int i;
74	static int setup;
75
76	if (!setup) {
77		for (i = 0; i < NUMCDEV; i++)
78			if (!bmaj2cmaj[i])
79				bmaj2cmaj[i] = 254;
80		setup++;
81	}
82
83	if ( *descrip == NODEV) {	/* auto (0 is valid) */
84		/*
85		 * Search the table looking for a slot...
86		 */
87		for (i = cdevsw_ALLOCSTART; i < nchrdev; i++)
88			if (cdevsw[i] == NULL)
89				break;		/* found one! */
90		/* out of allocable slots? */
91		if (i >= nchrdev) {
92			return ENFILE;
93		}
94	} else {				/* assign */
95		i = major(*descrip);
96		if (i < 0 || i >= nchrdev) {
97			return EINVAL;
98		}
99	}
100
101	/* maybe save old */
102        if (oldentry) {
103		*oldentry = cdevsw[i];
104	}
105	if (newentry) {
106		newentry->d_bmaj = -1;
107		newentry->d_maj = i;
108	}
109	/* replace with new */
110	cdevsw[i] = newentry;
111
112	/* done!  let them know where we put it */
113	*descrip = makedev(i,0);
114	return 0;
115}
116
117void
118cdevsw_add_generic(int bmaj, int cmaj, struct cdevsw *devsw)
119{
120	dev_t dev;
121
122	dev = makedev(cmaj, 0);
123	cdevsw_add(&dev, devsw, NULL);
124	cdevsw[cmaj]->d_bmaj = bmaj;
125	bmaj2cmaj[bmaj] = cmaj;
126}
127
128int
129devsw_module_handler(module_t mod, int what, void* arg)
130{
131	struct devsw_module_data* data = (struct devsw_module_data*) arg;
132	int error;
133
134	if (data->cmaj == NOMAJ)
135		data->cdev = NODEV;
136	else
137		data->cdev = makedev(data->cmaj, 0);
138	switch (what) {
139	case MOD_LOAD:
140		error = cdevsw_add(&data->cdev, data->cdevsw, NULL);
141		if (!error && data->cdevsw->d_strategy != nostrategy) {
142			if (data->bmaj == NOMAJ) {
143				data->bdev = data->cdev;
144				data->bmaj = data->cmaj;
145			} else {
146				data->bdev = makedev(data->bmaj, 0);
147			}
148			data->cdevsw->d_maj = data->bmaj;
149			bmaj2cmaj[major(data->bdev)] = major(data->cdev);
150		}
151		if (!error && data->chainevh)
152			error = data->chainevh(mod, what, data->chainarg);
153		return error;
154
155	case MOD_UNLOAD:
156		if (data->chainevh) {
157			error = data->chainevh(mod, what, data->chainarg);
158			if (error)
159				return error;
160		}
161		if (data->cdevsw->d_strategy != nostrategy)
162			bmaj2cmaj[major(data->bdev)] = 0;
163		error = cdevsw_add(&data->cdev, NULL, NULL);
164		return error;
165	}
166
167	if (data->chainevh)
168		return data->chainevh(mod, what, data->chainarg);
169	else
170		return 0;
171}
172
173/*
174 * dev_t and u_dev_t primitives
175 */
176
177#define DEVT_FASCIST 1
178
179int
180major(dev_t x)
181{
182	uintptr_t i = (uintptr_t)x;
183
184#ifdef DEVT_FASCIST
185	return(253 - ((i >> 8) & 0xff));
186#else
187	return((i >> 8) & 0xff);
188#endif
189}
190
191int
192minor(dev_t x)
193{
194	uintptr_t i = (uintptr_t)x;
195
196	return(i & 0xffff00ff);
197}
198
199dev_t
200makedev(int x, int y)
201{
202#ifdef DEVT_FASCIST
203        return ((dev_t) (((253 - 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