2005-04-17 00:20:36 +02:00
|
|
|
/*
|
|
|
|
* linux/drivers/char/misc.c
|
|
|
|
*
|
|
|
|
* Generic misc open routine by Johan Myreen
|
|
|
|
*
|
|
|
|
* Based on code from Linus
|
|
|
|
*
|
|
|
|
* Teemu Rantanen's Microsoft Busmouse support and Derrick Cole's
|
|
|
|
* changes incorporated into 0.97pl4
|
|
|
|
* by Peter Cervasio (pete%q106fm.uucp@wupost.wustl.edu) (08SEP92)
|
|
|
|
* See busmouse.c for particulars.
|
|
|
|
*
|
|
|
|
* Made things a lot mode modular - easy to compile in just one or two
|
|
|
|
* of the misc drivers, as they are now completely independent. Linus.
|
|
|
|
*
|
|
|
|
* Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk>
|
|
|
|
*
|
|
|
|
* Fixed a failing symbol register to free the device registration
|
|
|
|
* Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96
|
|
|
|
*
|
|
|
|
* Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96
|
|
|
|
*
|
|
|
|
* Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96
|
|
|
|
*
|
|
|
|
* Handling of mouse minor numbers for kerneld:
|
|
|
|
* Idea by Jacques Gelinas <jack@solucorp.qc.ca>,
|
|
|
|
* adapted by Bjorn Ekwall <bj0rn@blox.se>
|
|
|
|
* corrected by Alan Cox <alan@lxorguk.ukuu.org.uk>
|
|
|
|
*
|
|
|
|
* Changes for kmod (from kerneld):
|
|
|
|
* Cyrus Durgin <cider@speakeasy.org>
|
|
|
|
*
|
|
|
|
* Added devfs support. Richard Gooch <rgooch@atnf.csiro.au> 10-Jan-1998
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/module.h>
|
|
|
|
|
|
|
|
#include <linux/fs.h>
|
|
|
|
#include <linux/errno.h>
|
|
|
|
#include <linux/miscdevice.h>
|
|
|
|
#include <linux/kernel.h>
|
|
|
|
#include <linux/major.h>
|
|
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/proc_fs.h>
|
|
|
|
#include <linux/seq_file.h>
|
|
|
|
#include <linux/stat.h>
|
|
|
|
#include <linux/init.h>
|
|
|
|
#include <linux/device.h>
|
|
|
|
#include <linux/tty.h>
|
|
|
|
#include <linux/kmod.h>
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Head entry for the doubly linked miscdevice list
|
|
|
|
*/
|
|
|
|
static LIST_HEAD(misc_list);
|
|
|
|
static DECLARE_MUTEX(misc_sem);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Assigned numbers, used for dynamic minors
|
|
|
|
*/
|
|
|
|
#define DYNAMIC_MINORS 64 /* like dynamic majors */
|
|
|
|
static unsigned char misc_minors[DYNAMIC_MINORS / 8];
|
|
|
|
|
|
|
|
extern int pmu_device_init(void);
|
|
|
|
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
|
|
static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
|
|
|
|
{
|
|
|
|
struct miscdevice *p;
|
|
|
|
loff_t off = 0;
|
|
|
|
|
|
|
|
down(&misc_sem);
|
|
|
|
list_for_each_entry(p, &misc_list, list) {
|
|
|
|
if (*pos == off++)
|
|
|
|
return p;
|
|
|
|
}
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|
|
|
{
|
|
|
|
struct list_head *n = ((struct miscdevice *)v)->list.next;
|
|
|
|
|
|
|
|
++*pos;
|
|
|
|
|
|
|
|
return (n != &misc_list) ? list_entry(n, struct miscdevice, list)
|
|
|
|
: NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void misc_seq_stop(struct seq_file *seq, void *v)
|
|
|
|
{
|
|
|
|
up(&misc_sem);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int misc_seq_show(struct seq_file *seq, void *v)
|
|
|
|
{
|
|
|
|
const struct miscdevice *p = v;
|
|
|
|
|
|
|
|
seq_printf(seq, "%3i %s\n", p->minor, p->name ? p->name : "");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
static struct seq_operations misc_seq_ops = {
|
|
|
|
.start = misc_seq_start,
|
|
|
|
.next = misc_seq_next,
|
|
|
|
.stop = misc_seq_stop,
|
|
|
|
.show = misc_seq_show,
|
|
|
|
};
|
|
|
|
|
|
|
|
static int misc_seq_open(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
return seq_open(file, &misc_seq_ops);
|
|
|
|
}
|
|
|
|
|
2006-07-03 09:24:21 +02:00
|
|
|
static const struct file_operations misc_proc_fops = {
|
2005-04-17 00:20:36 +02:00
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.open = misc_seq_open,
|
|
|
|
.read = seq_read,
|
|
|
|
.llseek = seq_lseek,
|
|
|
|
.release = seq_release,
|
|
|
|
};
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static int misc_open(struct inode * inode, struct file * file)
|
|
|
|
{
|
|
|
|
int minor = iminor(inode);
|
|
|
|
struct miscdevice *c;
|
|
|
|
int err = -ENODEV;
|
2006-03-28 11:56:41 +02:00
|
|
|
const struct file_operations *old_fops, *new_fops = NULL;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
down(&misc_sem);
|
|
|
|
|
|
|
|
list_for_each_entry(c, &misc_list, list) {
|
|
|
|
if (c->minor == minor) {
|
|
|
|
new_fops = fops_get(c->fops);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!new_fops) {
|
|
|
|
up(&misc_sem);
|
|
|
|
request_module("char-major-%d-%d", MISC_MAJOR, minor);
|
|
|
|
down(&misc_sem);
|
|
|
|
|
|
|
|
list_for_each_entry(c, &misc_list, list) {
|
|
|
|
if (c->minor == minor) {
|
|
|
|
new_fops = fops_get(c->fops);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
if (!new_fops)
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
|
|
|
|
err = 0;
|
|
|
|
old_fops = file->f_op;
|
|
|
|
file->f_op = new_fops;
|
|
|
|
if (file->f_op->open) {
|
|
|
|
err=file->f_op->open(inode,file);
|
|
|
|
if (err) {
|
|
|
|
fops_put(file->f_op);
|
|
|
|
file->f_op = fops_get(old_fops);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
fops_put(old_fops);
|
|
|
|
fail:
|
|
|
|
up(&misc_sem);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2005-03-23 18:53:09 +01:00
|
|
|
static struct class *misc_class;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
2006-07-03 09:24:21 +02:00
|
|
|
static const struct file_operations misc_fops = {
|
2005-04-17 00:20:36 +02:00
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.open = misc_open,
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
* misc_register - register a miscellaneous device
|
|
|
|
* @misc: device structure
|
|
|
|
*
|
|
|
|
* Register a miscellaneous device with the kernel. If the minor
|
|
|
|
* number is set to %MISC_DYNAMIC_MINOR a minor number is assigned
|
|
|
|
* and placed in the minor field of the structure. For other cases
|
|
|
|
* the minor number requested is used.
|
|
|
|
*
|
|
|
|
* The structure passed is linked into the kernel and may not be
|
|
|
|
* destroyed until it has been unregistered.
|
|
|
|
*
|
|
|
|
* A zero is returned on success and a negative errno code for
|
|
|
|
* failure.
|
|
|
|
*/
|
|
|
|
|
|
|
|
int misc_register(struct miscdevice * misc)
|
|
|
|
{
|
|
|
|
struct miscdevice *c;
|
|
|
|
dev_t dev;
|
2005-06-21 06:15:16 +02:00
|
|
|
int err = 0;
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
down(&misc_sem);
|
|
|
|
list_for_each_entry(c, &misc_list, list) {
|
|
|
|
if (c->minor == misc->minor) {
|
|
|
|
up(&misc_sem);
|
|
|
|
return -EBUSY;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (misc->minor == MISC_DYNAMIC_MINOR) {
|
|
|
|
int i = DYNAMIC_MINORS;
|
|
|
|
while (--i >= 0)
|
|
|
|
if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
|
|
|
|
break;
|
|
|
|
if (i<0) {
|
|
|
|
up(&misc_sem);
|
|
|
|
return -EBUSY;
|
|
|
|
}
|
|
|
|
misc->minor = i;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (misc->minor < DYNAMIC_MINORS)
|
|
|
|
misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
|
|
|
|
dev = MKDEV(MISC_MAJOR, misc->minor);
|
|
|
|
|
2006-07-28 01:16:04 +02:00
|
|
|
misc->this_device = device_create(misc_class, misc->parent, dev,
|
2005-03-23 18:53:09 +01:00
|
|
|
"%s", misc->name);
|
2006-07-28 01:16:04 +02:00
|
|
|
if (IS_ERR(misc->this_device)) {
|
|
|
|
err = PTR_ERR(misc->this_device);
|
2005-04-17 00:20:36 +02:00
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Add it to the front, so that later devices can "override"
|
|
|
|
* earlier defaults
|
|
|
|
*/
|
|
|
|
list_add(&misc->list, &misc_list);
|
|
|
|
out:
|
|
|
|
up(&misc_sem);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* misc_deregister - unregister a miscellaneous device
|
|
|
|
* @misc: device to unregister
|
|
|
|
*
|
|
|
|
* Unregister a miscellaneous device that was previously
|
|
|
|
* successfully registered with misc_register(). Success
|
|
|
|
* is indicated by a zero return, a negative errno code
|
|
|
|
* indicates an error.
|
|
|
|
*/
|
|
|
|
|
|
|
|
int misc_deregister(struct miscdevice * misc)
|
|
|
|
{
|
|
|
|
int i = misc->minor;
|
|
|
|
|
|
|
|
if (list_empty(&misc->list))
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
down(&misc_sem);
|
|
|
|
list_del(&misc->list);
|
2006-07-28 01:16:04 +02:00
|
|
|
device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
|
2005-04-17 00:20:36 +02:00
|
|
|
if (i < DYNAMIC_MINORS && i>0) {
|
|
|
|
misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
|
|
|
|
}
|
|
|
|
up(&misc_sem);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
EXPORT_SYMBOL(misc_register);
|
|
|
|
EXPORT_SYMBOL(misc_deregister);
|
|
|
|
|
|
|
|
static int __init misc_init(void)
|
|
|
|
{
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
|
|
struct proc_dir_entry *ent;
|
|
|
|
|
|
|
|
ent = create_proc_entry("misc", 0, NULL);
|
|
|
|
if (ent)
|
|
|
|
ent->proc_fops = &misc_proc_fops;
|
|
|
|
#endif
|
2005-03-23 18:53:09 +01:00
|
|
|
misc_class = class_create(THIS_MODULE, "misc");
|
2005-04-17 00:20:36 +02:00
|
|
|
if (IS_ERR(misc_class))
|
|
|
|
return PTR_ERR(misc_class);
|
2005-09-07 00:16:58 +02:00
|
|
|
|
2005-04-17 00:20:36 +02:00
|
|
|
if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
|
|
|
|
printk("unable to get major %d for misc devices\n",
|
|
|
|
MISC_MAJOR);
|
2005-03-23 18:53:09 +01:00
|
|
|
class_destroy(misc_class);
|
2005-04-17 00:20:36 +02:00
|
|
|
return -EIO;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
subsys_initcall(misc_init);
|