kern_conf.c revision 48936 
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 1.50 1999/07/19 09:37:59 phk Exp $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/systm.h>
39#include <sys/module.h>
40#include <sys/malloc.h>
41#include <sys/conf.h>
42#include <sys/vnode.h>
43#include <sys/queue.h>
44
45#include <miscfs/specfs/specdev.h>
46
47#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
48
49struct cdevsw 	*cdevsw[NUMCDEVSW];
50
51static int	bmaj2cmaj[NUMCDEVSW];
52
53MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
54
55#define DEVT_HASH 83
56#define DEVT_STASH 50
57
58static struct specinfo devt_stash[DEVT_STASH];
59
60static SLIST_HEAD(devt_hash_head, specinfo) dev_hash[DEVT_HASH];
61
62/*
63 * Routine to convert from character to block device number.
64 *
65 * A minimal stub routine can always return NODEV.
66 */
67dev_t
68chrtoblk(dev_t dev)
69{
70	struct cdevsw *cd;
71
72	if((cd = devsw(dev)) != NULL) {
73          if (cd->d_bmaj != -1)
74	    return(makebdev(cd->d_bmaj,minor(dev)));
75	}
76	return(NODEV);
77}
78
79struct cdevsw *
80devsw(dev_t dev)
81{
82        return(cdevsw[major(dev)]);
83}
84
85struct cdevsw *
86bdevsw(dev_t dev)
87{
88        return(cdevsw[major(dev)]);
89}
90
91/*
92 *  Add a cdevsw entry
93 */
94
95int
96cdevsw_add(struct cdevsw *newentry)
97{
98	int i;
99	static int setup;
100
101	if (!setup) {
102		for (i = 0; i < NUMCDEVSW; i++)
103			if (!bmaj2cmaj[i])
104				bmaj2cmaj[i] = 254;
105		setup++;
106	}
107
108	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
109		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
110		    newentry->d_name, newentry->d_maj);
111		return EINVAL;
112	}
113
114	if (cdevsw[newentry->d_maj]) {
115		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
116		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
117	}
118	cdevsw[newentry->d_maj] = newentry;
119
120	if (newentry->d_bmaj >= 0 && newentry->d_bmaj < NUMCDEVSW) {
121		if (bmaj2cmaj[newentry->d_bmaj] != 254) {
122			printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n",
123			    newentry->d_name,
124			    cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name);
125		}
126		bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
127	}
128
129	return 0;
130}
131
132/*
133 *  Remove a cdevsw entry
134 */
135
136int
137cdevsw_remove(struct cdevsw *oldentry)
138{
139	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
140		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
141		    oldentry->d_name, oldentry->d_maj);
142		return EINVAL;
143	}
144
145	cdevsw[oldentry->d_maj] = NULL;
146
147	if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW)
148		bmaj2cmaj[oldentry->d_bmaj] = NULL;
149
150	return 0;
151}
152
153int
154devsw_module_handler(module_t mod, int what, void* arg)
155{
156	struct devsw_module_data* data = (struct devsw_module_data*) arg;
157	int error = 0;
158
159	switch (what) {
160	case MOD_LOAD:
161		error = cdevsw_add(data->cdevsw);
162		if (!error && data->chainevh)
163			error = data->chainevh(mod, what, data->chainarg);
164		return error;
165
166	case MOD_UNLOAD:
167		if (data->chainevh) {
168			error = data->chainevh(mod, what, data->chainarg);
169			if (error)
170				return error;
171		}
172		cdevsw_remove(data->cdevsw);
173		return error;
174	}
175
176	if (data->chainevh)
177		return data->chainevh(mod, what, data->chainarg);
178	else
179		return 0;
180}
181
182/*
183 * dev_t and u_dev_t primitives
184 */
185
186int
187major(dev_t x)
188{
189	if (x == NODEV)
190		return NOUDEV;
191	return((x->si_udev >> 8) & 0xff);
192}
193
194int
195minor(dev_t x)
196{
197	if (x == NODEV)
198		return NOUDEV;
199	return(x->si_udev & 0xffff00ff);
200}
201
202dev_t
203makebdev(int x, int y)
204{
205	return (makedev(bmaj2cmaj[x], y));
206}
207
208dev_t
209makedev(int x, int y)
210{
211	struct specinfo *si;
212	udev_t	udev;
213	int hash;
214	static int stashed;
215
216	udev = (x << 8) | y;
217	hash = udev % DEVT_HASH;
218	SLIST_FOREACH(si, &dev_hash[hash], si_hash) {
219		if (si->si_udev == udev)
220			return (si);
221	}
222	if (stashed >= DEVT_STASH) {
223		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
224		    M_USE_RESERVE);
225	} else {
226		si = devt_stash + stashed++;
227	}
228	bzero(si, sizeof(*si));
229	si->si_udev = udev;
230	si->si_bsize_phys = DEV_BSIZE;
231	si->si_bsize_best = BLKDEV_IOSIZE;
232	si->si_bsize_max = MAXBSIZE;
233	SLIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
234        return (si);
235}
236
237udev_t
238dev2udev(dev_t x)
239{
240	if (x == NODEV)
241		return NOUDEV;
242	return (x->si_udev);
243}
244
245dev_t
246udev2dev(udev_t x, int b)
247{
248	switch (b) {
249		case 0:
250			return makedev(umajor(x), uminor(x));
251		case 1:
252			return makebdev(umajor(x), uminor(x));
253		default:
254			Debugger("udev2dev(...,X)");
255			return NODEV;
256	}
257}
258
259int
260uminor(udev_t dev)
261{
262	return(dev & 0xffff00ff);
263}
264
265int
266umajor(udev_t dev)
267{
268	return((dev & 0xff00) >> 8);
269}
270
271udev_t
272makeudev(int x, int y)
273{
274        return ((x << 8) | y);
275}
276
277