Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/misc.c | |
3 | * | |
4 | * Generic misc open routine by Johan Myreen | |
5 | * | |
6 | * Based on code from Linus | |
7 | * | |
8 | * Teemu Rantanen's Microsoft Busmouse support and Derrick Cole's | |
9 | * changes incorporated into 0.97pl4 | |
10 | * by Peter Cervasio (pete%q106fm.uucp@wupost.wustl.edu) (08SEP92) | |
11 | * See busmouse.c for particulars. | |
12 | * | |
13 | * Made things a lot mode modular - easy to compile in just one or two | |
14 | * of the misc drivers, as they are now completely independent. Linus. | |
15 | * | |
16 | * Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk> | |
17 | * | |
18 | * Fixed a failing symbol register to free the device registration | |
19 | * Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96 | |
20 | * | |
21 | * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96 | |
22 | * | |
23 | * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96 | |
24 | * | |
25 | * Handling of mouse minor numbers for kerneld: | |
26 | * Idea by Jacques Gelinas <jack@solucorp.qc.ca>, | |
27 | * adapted by Bjorn Ekwall <bj0rn@blox.se> | |
28 | * corrected by Alan Cox <alan@lxorguk.ukuu.org.uk> | |
29 | * | |
30 | * Changes for kmod (from kerneld): | |
31 | * Cyrus Durgin <cider@speakeasy.org> | |
32 | * | |
33 | * Added devfs support. Richard Gooch <rgooch@atnf.csiro.au> 10-Jan-1998 | |
34 | */ | |
35 | ||
36 | #include <linux/module.h> | |
37 | #include <linux/config.h> | |
38 | ||
39 | #include <linux/fs.h> | |
40 | #include <linux/errno.h> | |
41 | #include <linux/miscdevice.h> | |
42 | #include <linux/kernel.h> | |
43 | #include <linux/major.h> | |
44 | #include <linux/slab.h> | |
45 | #include <linux/proc_fs.h> | |
46 | #include <linux/seq_file.h> | |
47 | #include <linux/devfs_fs_kernel.h> | |
48 | #include <linux/stat.h> | |
49 | #include <linux/init.h> | |
50 | #include <linux/device.h> | |
51 | #include <linux/tty.h> | |
52 | #include <linux/kmod.h> | |
53 | ||
54 | /* | |
55 | * Head entry for the doubly linked miscdevice list | |
56 | */ | |
57 | static LIST_HEAD(misc_list); | |
58 | static DECLARE_MUTEX(misc_sem); | |
59 | ||
60 | /* | |
61 | * Assigned numbers, used for dynamic minors | |
62 | */ | |
63 | #define DYNAMIC_MINORS 64 /* like dynamic majors */ | |
64 | static unsigned char misc_minors[DYNAMIC_MINORS / 8]; | |
65 | ||
66 | extern int rtc_DP8570A_init(void); | |
67 | extern int rtc_MK48T08_init(void); | |
68 | extern int pmu_device_init(void); | |
69 | extern int tosh_init(void); | |
70 | extern int i8k_init(void); | |
71 | ||
72 | #ifdef CONFIG_PROC_FS | |
73 | static void *misc_seq_start(struct seq_file *seq, loff_t *pos) | |
74 | { | |
75 | struct miscdevice *p; | |
76 | loff_t off = 0; | |
77 | ||
78 | down(&misc_sem); | |
79 | list_for_each_entry(p, &misc_list, list) { | |
80 | if (*pos == off++) | |
81 | return p; | |
82 | } | |
83 | return NULL; | |
84 | } | |
85 | ||
86 | static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos) | |
87 | { | |
88 | struct list_head *n = ((struct miscdevice *)v)->list.next; | |
89 | ||
90 | ++*pos; | |
91 | ||
92 | return (n != &misc_list) ? list_entry(n, struct miscdevice, list) | |
93 | : NULL; | |
94 | } | |
95 | ||
96 | static void misc_seq_stop(struct seq_file *seq, void *v) | |
97 | { | |
98 | up(&misc_sem); | |
99 | } | |
100 | ||
101 | static int misc_seq_show(struct seq_file *seq, void *v) | |
102 | { | |
103 | const struct miscdevice *p = v; | |
104 | ||
105 | seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : ""); | |
106 | return 0; | |
107 | } | |
108 | ||
109 | ||
110 | static struct seq_operations misc_seq_ops = { | |
111 | .start = misc_seq_start, | |
112 | .next = misc_seq_next, | |
113 | .stop = misc_seq_stop, | |
114 | .show = misc_seq_show, | |
115 | }; | |
116 | ||
117 | static int misc_seq_open(struct inode *inode, struct file *file) | |
118 | { | |
119 | return seq_open(file, &misc_seq_ops); | |
120 | } | |
121 | ||
122 | static struct file_operations misc_proc_fops = { | |
123 | .owner = THIS_MODULE, | |
124 | .open = misc_seq_open, | |
125 | .read = seq_read, | |
126 | .llseek = seq_lseek, | |
127 | .release = seq_release, | |
128 | }; | |
129 | #endif | |
130 | ||
131 | static int misc_open(struct inode * inode, struct file * file) | |
132 | { | |
133 | int minor = iminor(inode); | |
134 | struct miscdevice *c; | |
135 | int err = -ENODEV; | |
136 | struct file_operations *old_fops, *new_fops = NULL; | |
137 | ||
138 | down(&misc_sem); | |
139 | ||
140 | list_for_each_entry(c, &misc_list, list) { | |
141 | if (c->minor == minor) { | |
142 | new_fops = fops_get(c->fops); | |
143 | break; | |
144 | } | |
145 | } | |
146 | ||
147 | if (!new_fops) { | |
148 | up(&misc_sem); | |
149 | request_module("char-major-%d-%d", MISC_MAJOR, minor); | |
150 | down(&misc_sem); | |
151 | ||
152 | list_for_each_entry(c, &misc_list, list) { | |
153 | if (c->minor == minor) { | |
154 | new_fops = fops_get(c->fops); | |
155 | break; | |
156 | } | |
157 | } | |
158 | if (!new_fops) | |
159 | goto fail; | |
160 | } | |
161 | ||
162 | err = 0; | |
163 | old_fops = file->f_op; | |
164 | file->f_op = new_fops; | |
165 | if (file->f_op->open) { | |
166 | err=file->f_op->open(inode,file); | |
167 | if (err) { | |
168 | fops_put(file->f_op); | |
169 | file->f_op = fops_get(old_fops); | |
170 | } | |
171 | } | |
172 | fops_put(old_fops); | |
173 | fail: | |
174 | up(&misc_sem); | |
175 | return err; | |
176 | } | |
177 | ||
178 | /* | |
179 | * TODO for 2.7: | |
ca8eca68 | 180 | * - add a struct kref to struct miscdevice and make all usages of |
1da177e4 LT |
181 | * them dynamic. |
182 | */ | |
ca8eca68 | 183 | static struct class *misc_class; |
1da177e4 LT |
184 | |
185 | static struct file_operations misc_fops = { | |
186 | .owner = THIS_MODULE, | |
187 | .open = misc_open, | |
188 | }; | |
189 | ||
190 | ||
191 | /** | |
192 | * misc_register - register a miscellaneous device | |
193 | * @misc: device structure | |
194 | * | |
195 | * Register a miscellaneous device with the kernel. If the minor | |
196 | * number is set to %MISC_DYNAMIC_MINOR a minor number is assigned | |
197 | * and placed in the minor field of the structure. For other cases | |
198 | * the minor number requested is used. | |
199 | * | |
200 | * The structure passed is linked into the kernel and may not be | |
201 | * destroyed until it has been unregistered. | |
202 | * | |
203 | * A zero is returned on success and a negative errno code for | |
204 | * failure. | |
205 | */ | |
206 | ||
207 | int misc_register(struct miscdevice * misc) | |
208 | { | |
209 | struct miscdevice *c; | |
210 | dev_t dev; | |
211 | int err; | |
212 | ||
213 | down(&misc_sem); | |
214 | list_for_each_entry(c, &misc_list, list) { | |
215 | if (c->minor == misc->minor) { | |
216 | up(&misc_sem); | |
217 | return -EBUSY; | |
218 | } | |
219 | } | |
220 | ||
221 | if (misc->minor == MISC_DYNAMIC_MINOR) { | |
222 | int i = DYNAMIC_MINORS; | |
223 | while (--i >= 0) | |
224 | if ( (misc_minors[i>>3] & (1 << (i&7))) == 0) | |
225 | break; | |
226 | if (i<0) { | |
227 | up(&misc_sem); | |
228 | return -EBUSY; | |
229 | } | |
230 | misc->minor = i; | |
231 | } | |
232 | ||
233 | if (misc->minor < DYNAMIC_MINORS) | |
234 | misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7); | |
235 | if (misc->devfs_name[0] == '\0') { | |
236 | snprintf(misc->devfs_name, sizeof(misc->devfs_name), | |
237 | "misc/%s", misc->name); | |
238 | } | |
239 | dev = MKDEV(MISC_MAJOR, misc->minor); | |
240 | ||
ca8eca68 | 241 | misc->class = class_device_create(misc_class, dev, misc->dev, |
242 | "%s", misc->name); | |
1da177e4 LT |
243 | if (IS_ERR(misc->class)) { |
244 | err = PTR_ERR(misc->class); | |
245 | goto out; | |
246 | } | |
247 | ||
248 | err = devfs_mk_cdev(dev, S_IFCHR|S_IRUSR|S_IWUSR|S_IRGRP, | |
249 | misc->devfs_name); | |
250 | if (err) { | |
ca8eca68 | 251 | class_device_destroy(misc_class, dev); |
1da177e4 LT |
252 | goto out; |
253 | } | |
254 | ||
255 | /* | |
256 | * Add it to the front, so that later devices can "override" | |
257 | * earlier defaults | |
258 | */ | |
259 | list_add(&misc->list, &misc_list); | |
260 | out: | |
261 | up(&misc_sem); | |
262 | return err; | |
263 | } | |
264 | ||
265 | /** | |
266 | * misc_deregister - unregister a miscellaneous device | |
267 | * @misc: device to unregister | |
268 | * | |
269 | * Unregister a miscellaneous device that was previously | |
270 | * successfully registered with misc_register(). Success | |
271 | * is indicated by a zero return, a negative errno code | |
272 | * indicates an error. | |
273 | */ | |
274 | ||
275 | int misc_deregister(struct miscdevice * misc) | |
276 | { | |
277 | int i = misc->minor; | |
278 | ||
279 | if (list_empty(&misc->list)) | |
280 | return -EINVAL; | |
281 | ||
282 | down(&misc_sem); | |
283 | list_del(&misc->list); | |
ca8eca68 | 284 | class_device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor)); |
1da177e4 LT |
285 | devfs_remove(misc->devfs_name); |
286 | if (i < DYNAMIC_MINORS && i>0) { | |
287 | misc_minors[i>>3] &= ~(1 << (misc->minor & 7)); | |
288 | } | |
289 | up(&misc_sem); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | EXPORT_SYMBOL(misc_register); | |
294 | EXPORT_SYMBOL(misc_deregister); | |
295 | ||
296 | static int __init misc_init(void) | |
297 | { | |
298 | #ifdef CONFIG_PROC_FS | |
299 | struct proc_dir_entry *ent; | |
300 | ||
301 | ent = create_proc_entry("misc", 0, NULL); | |
302 | if (ent) | |
303 | ent->proc_fops = &misc_proc_fops; | |
304 | #endif | |
ca8eca68 | 305 | misc_class = class_create(THIS_MODULE, "misc"); |
1da177e4 LT |
306 | if (IS_ERR(misc_class)) |
307 | return PTR_ERR(misc_class); | |
308 | #ifdef CONFIG_MVME16x | |
309 | rtc_MK48T08_init(); | |
310 | #endif | |
311 | #ifdef CONFIG_BVME6000 | |
312 | rtc_DP8570A_init(); | |
313 | #endif | |
314 | #ifdef CONFIG_PMAC_PBOOK | |
315 | pmu_device_init(); | |
316 | #endif | |
317 | #ifdef CONFIG_TOSHIBA | |
318 | tosh_init(); | |
319 | #endif | |
320 | #ifdef CONFIG_I8K | |
321 | i8k_init(); | |
322 | #endif | |
323 | if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) { | |
324 | printk("unable to get major %d for misc devices\n", | |
325 | MISC_MAJOR); | |
ca8eca68 | 326 | class_destroy(misc_class); |
1da177e4 LT |
327 | return -EIO; |
328 | } | |
329 | return 0; | |
330 | } | |
331 | subsys_initcall(misc_init); |