2 * linux/drivers/char/misc.c
4 * Generic misc open routine by Johan Myreen
6 * Based on code from Linus
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.
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.
16 * Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk>
18 * Fixed a failing symbol register to free the device registration
19 * Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96
21 * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96
23 * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96
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>
30 * Changes for kmod (from kerneld):
31 * Cyrus Durgin <cider@speakeasy.org>
33 * Added devfs support. Richard Gooch <rgooch@atnf.csiro.au> 10-Jan-1998
36 #include <linux/module.h>
37 #include <linux/config.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>
55 * Head entry for the doubly linked miscdevice list
57 static LIST_HEAD(misc_list);
58 static DECLARE_MUTEX(misc_sem);
61 * Assigned numbers, used for dynamic minors
63 #define DYNAMIC_MINORS 64 /* like dynamic majors */
64 static unsigned char misc_minors[DYNAMIC_MINORS / 8];
66 #ifdef CONFIG_SGI_NEWPORT_GFX
67 extern void gfx_register(void);
69 extern void streamable_init(void);
70 extern int rtc_DP8570A_init(void);
71 extern int rtc_MK48T08_init(void);
72 extern int ds1286_init(void);
73 extern int pmu_device_init(void);
74 extern int tosh_init(void);
75 extern int i8k_init(void);
78 static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
84 list_for_each_entry(p, &misc_list, list) {
91 static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
93 struct list_head *n = ((struct miscdevice *)v)->list.next;
97 return (n != &misc_list) ? list_entry(n, struct miscdevice, list)
101 static void misc_seq_stop(struct seq_file *seq, void *v)
106 static int misc_seq_show(struct seq_file *seq, void *v)
108 const struct miscdevice *p = v;
110 seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");
115 static struct seq_operations misc_seq_ops = {
116 .start = misc_seq_start,
117 .next = misc_seq_next,
118 .stop = misc_seq_stop,
119 .show = misc_seq_show,
122 static int misc_seq_open(struct inode *inode, struct file *file)
124 return seq_open(file, &misc_seq_ops);
127 static struct file_operations misc_proc_fops = {
128 .owner = THIS_MODULE,
129 .open = misc_seq_open,
132 .release = seq_release,
136 static int misc_open(struct inode * inode, struct file * file)
138 int minor = iminor(inode);
139 struct miscdevice *c;
141 struct file_operations *old_fops, *new_fops = NULL;
145 list_for_each_entry(c, &misc_list, list) {
146 if (c->minor == minor) {
147 new_fops = fops_get(c->fops);
154 request_module("char-major-%d-%d", MISC_MAJOR, minor);
157 list_for_each_entry(c, &misc_list, list) {
158 if (c->minor == minor) {
159 new_fops = fops_get(c->fops);
168 old_fops = file->f_op;
169 file->f_op = new_fops;
170 if (file->f_op->open) {
171 err=file->f_op->open(inode,file);
173 fops_put(file->f_op);
174 file->f_op = fops_get(old_fops);
185 * - add a struct class_device to struct miscdevice and make all usages of
188 static struct class_simple *misc_class;
190 static struct file_operations misc_fops = {
191 .owner = THIS_MODULE,
197 * misc_register - register a miscellaneous device
198 * @misc: device structure
200 * Register a miscellaneous device with the kernel. If the minor
201 * number is set to %MISC_DYNAMIC_MINOR a minor number is assigned
202 * and placed in the minor field of the structure. For other cases
203 * the minor number requested is used.
205 * The structure passed is linked into the kernel and may not be
206 * destroyed until it has been unregistered.
208 * A zero is returned on success and a negative errno code for
212 int misc_register(struct miscdevice * misc)
214 struct miscdevice *c;
215 struct class_device *class;
220 list_for_each_entry(c, &misc_list, list) {
221 if (c->minor == misc->minor) {
227 if (misc->minor == MISC_DYNAMIC_MINOR) {
228 int i = DYNAMIC_MINORS;
230 if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
240 if (misc->minor < DYNAMIC_MINORS)
241 misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
242 if (misc->devfs_name[0] == '\0') {
243 snprintf(misc->devfs_name, sizeof(misc->devfs_name),
244 "misc/%s", misc->name);
246 dev = MKDEV(MISC_MAJOR, misc->minor);
248 class = class_simple_device_add(misc_class, dev,
249 misc->dev, misc->name);
251 err = PTR_ERR(class);
255 err = devfs_mk_cdev(dev, S_IFCHR|S_IRUSR|S_IWUSR|S_IRGRP,
258 class_simple_device_remove(dev);
263 * Add it to the front, so that later devices can "override"
266 list_add(&misc->list, &misc_list);
273 * misc_deregister - unregister a miscellaneous device
274 * @misc: device to unregister
276 * Unregister a miscellaneous device that was previously
277 * successfully registered with misc_register(). Success
278 * is indicated by a zero return, a negative errno code
279 * indicates an error.
282 int misc_deregister(struct miscdevice * misc)
286 if (list_empty(&misc->list))
290 list_del(&misc->list);
291 class_simple_device_remove(MKDEV(MISC_MAJOR, misc->minor));
292 devfs_remove(misc->devfs_name);
293 if (i < DYNAMIC_MINORS && i>0) {
294 misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
300 EXPORT_SYMBOL(misc_register);
301 EXPORT_SYMBOL(misc_deregister);
303 static int __init misc_init(void)
305 #ifdef CONFIG_PROC_FS
306 struct proc_dir_entry *ent;
308 ent = create_proc_entry("misc", 0, NULL);
310 ent->proc_fops = &misc_proc_fops;
312 misc_class = class_simple_create(THIS_MODULE, "misc");
313 if (IS_ERR(misc_class))
314 return PTR_ERR(misc_class);
315 #ifdef CONFIG_MVME16x
318 #ifdef CONFIG_BVME6000
321 #ifdef CONFIG_SGI_DS1286
324 #ifdef CONFIG_PMAC_PBOOK
327 #ifdef CONFIG_SGI_NEWPORT_GFX
330 #ifdef CONFIG_SGI_IP22
333 #ifdef CONFIG_SGI_NEWPORT_GFX
336 #ifdef CONFIG_TOSHIBA
342 if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
343 printk("unable to get major %d for misc devices\n",
345 class_simple_destroy(misc_class);
350 subsys_initcall(misc_init);