1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/*
* drivers/usb/file.c
*
* (C) Copyright Linus Torvalds 1999
* (C) Copyright Johannes Erdfelt 1999-2001
* (C) Copyright Andreas Gal 1999
* (C) Copyright Gregory P. Smith 1999
* (C) Copyright Deti Fliegl 1999 (new USB architecture)
* (C) Copyright Randy Dunlap 2000
* (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
more docs, etc)
* (C) Copyright Yggdrasil Computing, Inc. 2000
* (usb_device_id matching changes by Adam J. Richter)
* (C) Copyright Greg Kroah-Hartman 2002-2003
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#ifdef CONFIG_USB_DEBUG
#define DEBUG
#else
#undef DEBUG
#endif
#include <linux/usb.h>
#include "usb.h"
#define MAX_USB_MINORS 256
static struct file_operations *usb_minors[MAX_USB_MINORS];
static DEFINE_SPINLOCK(minor_lock);
static int usb_open(struct inode * inode, struct file * file)
{
int minor = iminor(inode);
struct file_operations *c;
int err = -ENODEV;
struct file_operations *old_fops, *new_fops = NULL;
spin_lock (&minor_lock);
c = usb_minors[minor];
if (!c || !(new_fops = fops_get(c))) {
spin_unlock(&minor_lock);
return err;
}
spin_unlock(&minor_lock);
old_fops = file->f_op;
file->f_op = new_fops;
/* Curiouser and curiouser... NULL ->open() as "no device" ? */
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);
return err;
}
static struct file_operations usb_fops = {
.owner = THIS_MODULE,
.open = usb_open,
};
static struct class *usb_class;
int usb_major_init(void)
{
int error;
error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
if (error) {
err("unable to get major %d for usb devices", USB_MAJOR);
goto out;
}
usb_class = class_create(THIS_MODULE, "usb");
if (IS_ERR(usb_class)) {
error = PTR_ERR(usb_class);
err("class_create failed for usb devices");
unregister_chrdev(USB_MAJOR, "usb");
goto out;
}
devfs_mk_dir("usb");
out:
return error;
}
void usb_major_cleanup(void)
{
class_destroy(usb_class);
devfs_remove("usb");
unregister_chrdev(USB_MAJOR, "usb");
}
/**
* usb_register_dev - register a USB device, and ask for a minor number
* @intf: pointer to the usb_interface that is being registered
* @class_driver: pointer to the usb_class_driver for this device
*
* This should be called by all USB drivers that use the USB major number.
* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
* dynamically allocated out of the list of available ones. If it is not
* enabled, the minor number will be based on the next available free minor,
* starting at the class_driver->minor_base.
*
* This function also creates the devfs file for the usb device, if devfs
* is enabled, and creates a usb class device in the sysfs tree.
*
* usb_deregister_dev() must be called when the driver is done with
* the minor numbers given out by this function.
*
* Returns -EINVAL if something bad happens with trying to register a
* device, and 0 on success.
*/
int usb_register_dev(struct usb_interface *intf,
struct usb_class_driver *class_driver)
{
int retval = -EINVAL;
int minor_base = class_driver->minor_base;
int minor = 0;
char name[BUS_ID_SIZE];
char *temp;
#ifdef CONFIG_USB_DYNAMIC_MINORS
/*
* We don't care what the device tries to start at, we want to start
* at zero to pack the devices into the smallest available space with
* no holes in the minor range.
*/
minor_base = 0;
#endif
intf->minor = -1;
dbg ("looking for a minor, starting at %d", minor_base);
if (class_driver->fops == NULL)
goto exit;
spin_lock (&minor_lock);
for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
if (usb_minors[minor])
continue;
usb_minors[minor] = class_driver->fops;
retval = 0;
break;
}
spin_unlock (&minor_lock);
if (retval)
goto exit;
intf->minor = minor;
/* handle the devfs registration */
snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
devfs_mk_cdev(MKDEV(USB_MAJOR, minor), class_driver->mode, name);
/* create a usb class device for this usb interface */
temp = strrchr(name, '/');
if (temp && (temp[1] != 0x00))
++temp;
else
temp = name;
intf->class_dev = class_device_create(usb_class, NULL,
MKDEV(USB_MAJOR, minor),
&intf->dev, "%s", temp);
if (IS_ERR(intf->class_dev)) {
spin_lock (&minor_lock);
usb_minors[intf->minor] = NULL;
spin_unlock (&minor_lock);
devfs_remove (name);
retval = PTR_ERR(intf->class_dev);
}
exit:
return retval;
}
EXPORT_SYMBOL(usb_register_dev);
/**
* usb_deregister_dev - deregister a USB device's dynamic minor.
* @intf: pointer to the usb_interface that is being deregistered
* @class_driver: pointer to the usb_class_driver for this device
*
* Used in conjunction with usb_register_dev(). This function is called
* when the USB driver is finished with the minor numbers gotten from a
* call to usb_register_dev() (usually when the device is disconnected
* from the system.)
*
* This function also cleans up the devfs file for the usb device, if devfs
* is enabled, and removes the usb class device from the sysfs tree.
*
* This should be called by all drivers that use the USB major number.
*/
void usb_deregister_dev(struct usb_interface *intf,
struct usb_class_driver *class_driver)
{
int minor_base = class_driver->minor_base;
char name[BUS_ID_SIZE];
#ifdef CONFIG_USB_DYNAMIC_MINORS
minor_base = 0;
#endif
if (intf->minor == -1)
return;
dbg ("removing %d minor", intf->minor);
spin_lock (&minor_lock);
usb_minors[intf->minor] = NULL;
spin_unlock (&minor_lock);
snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
devfs_remove (name);
class_device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor));
intf->class_dev = NULL;
intf->minor = -1;
}
EXPORT_SYMBOL(usb_deregister_dev);
|
