Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/drivers/char/misc.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 7507 byte(s)
Tag kernel26-2.6.12-alx-r9
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: |
180 | * - add a struct class_device to struct miscdevice and make all usages of |
181 | * them dynamic. |
182 | */ |
183 | static struct class_simple *misc_class; |
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 | |
241 | misc->class = class_simple_device_add(misc_class, dev, |
242 | misc->dev, misc->name); |
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) { |
251 | class_simple_device_remove(dev); |
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); |
284 | class_simple_device_remove(MKDEV(MISC_MAJOR, misc->minor)); |
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 |
305 | misc_class = class_simple_create(THIS_MODULE, "misc"); |
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); |
326 | class_simple_destroy(misc_class); |
327 | return -EIO; |
328 | } |
329 | return 0; |
330 | } |
331 | subsys_initcall(misc_init); |