2 * drivers/usb/core/file.c
4 * (C) Copyright Linus Torvalds 1999
5 * (C) Copyright Johannes Erdfelt 1999-2001
6 * (C) Copyright Andreas Gal 1999
7 * (C) Copyright Gregory P. Smith 1999
8 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
9 * (C) Copyright Randy Dunlap 2000
10 * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
12 * (C) Copyright Yggdrasil Computing, Inc. 2000
13 * (usb_device_id matching changes by Adam J. Richter)
14 * (C) Copyright Greg Kroah-Hartman 2002-2003
18 #include <linux/module.h>
19 #include <linux/errno.h>
20 #include <linux/rwsem.h>
21 #include <linux/smp_lock.h>
22 #include <linux/usb.h>
26 #define MAX_USB_MINORS 256
27 static const struct file_operations
*usb_minors
[MAX_USB_MINORS
];
28 static DECLARE_RWSEM(minor_rwsem
);
30 static int usb_open(struct inode
* inode
, struct file
* file
)
32 int minor
= iminor(inode
);
33 const struct file_operations
*c
;
35 const struct file_operations
*old_fops
, *new_fops
= NULL
;
37 down_read(&minor_rwsem
);
38 c
= usb_minors
[minor
];
40 if (!c
|| !(new_fops
= fops_get(c
)))
43 old_fops
= file
->f_op
;
44 file
->f_op
= new_fops
;
45 /* Curiouser and curiouser... NULL ->open() as "no device" ? */
47 err
= file
->f_op
->open(inode
,file
);
50 file
->f_op
= fops_get(old_fops
);
54 up_read(&minor_rwsem
);
58 static const struct file_operations usb_fops
= {
63 static struct usb_class
{
68 static char *usb_devnode(struct device
*dev
, mode_t
*mode
)
70 struct usb_class_driver
*drv
;
72 drv
= dev_get_drvdata(dev
);
73 if (!drv
|| !drv
->devnode
)
75 return drv
->devnode(dev
, mode
);
78 static int init_usb_class(void)
82 if (usb_class
!= NULL
) {
83 kref_get(&usb_class
->kref
);
87 usb_class
= kmalloc(sizeof(*usb_class
), GFP_KERNEL
);
93 kref_init(&usb_class
->kref
);
94 usb_class
->class = class_create(THIS_MODULE
, "usb");
95 if (IS_ERR(usb_class
->class)) {
96 result
= IS_ERR(usb_class
->class);
97 printk(KERN_ERR
"class_create failed for usb devices\n");
102 usb_class
->class->devnode
= usb_devnode
;
108 static void release_usb_class(struct kref
*kref
)
110 /* Ok, we cheat as we know we only have one usb_class */
111 class_destroy(usb_class
->class);
116 static void destroy_usb_class(void)
119 kref_put(&usb_class
->kref
, release_usb_class
);
122 int usb_major_init(void)
126 error
= register_chrdev(USB_MAJOR
, "usb", &usb_fops
);
128 printk(KERN_ERR
"Unable to get major %d for usb devices\n",
134 void usb_major_cleanup(void)
136 unregister_chrdev(USB_MAJOR
, "usb");
140 * usb_register_dev - register a USB device, and ask for a minor number
141 * @intf: pointer to the usb_interface that is being registered
142 * @class_driver: pointer to the usb_class_driver for this device
144 * This should be called by all USB drivers that use the USB major number.
145 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
146 * dynamically allocated out of the list of available ones. If it is not
147 * enabled, the minor number will be based on the next available free minor,
148 * starting at the class_driver->minor_base.
150 * This function also creates a usb class device in the sysfs tree.
152 * usb_deregister_dev() must be called when the driver is done with
153 * the minor numbers given out by this function.
155 * Returns -EINVAL if something bad happens with trying to register a
156 * device, and 0 on success.
158 int usb_register_dev(struct usb_interface
*intf
,
159 struct usb_class_driver
*class_driver
)
161 int retval
= -EINVAL
;
162 int minor_base
= class_driver
->minor_base
;
167 #ifdef CONFIG_USB_DYNAMIC_MINORS
169 * We don't care what the device tries to start at, we want to start
170 * at zero to pack the devices into the smallest available space with
171 * no holes in the minor range.
177 dbg ("looking for a minor, starting at %d", minor_base
);
179 if (class_driver
->fops
== NULL
)
182 down_write(&minor_rwsem
);
183 for (minor
= minor_base
; minor
< MAX_USB_MINORS
; ++minor
) {
184 if (usb_minors
[minor
])
187 usb_minors
[minor
] = class_driver
->fops
;
192 up_write(&minor_rwsem
);
197 retval
= init_usb_class();
203 /* create a usb class device for this usb interface */
204 snprintf(name
, sizeof(name
), class_driver
->name
, minor
- minor_base
);
205 temp
= strrchr(name
, '/');
206 if (temp
&& (temp
[1] != '\0'))
210 intf
->usb_dev
= device_create(usb_class
->class, &intf
->dev
,
211 MKDEV(USB_MAJOR
, minor
), class_driver
,
213 if (IS_ERR(intf
->usb_dev
)) {
214 down_write(&minor_rwsem
);
215 usb_minors
[intf
->minor
] = NULL
;
216 up_write(&minor_rwsem
);
217 retval
= PTR_ERR(intf
->usb_dev
);
222 EXPORT_SYMBOL_GPL(usb_register_dev
);
225 * usb_deregister_dev - deregister a USB device's dynamic minor.
226 * @intf: pointer to the usb_interface that is being deregistered
227 * @class_driver: pointer to the usb_class_driver for this device
229 * Used in conjunction with usb_register_dev(). This function is called
230 * when the USB driver is finished with the minor numbers gotten from a
231 * call to usb_register_dev() (usually when the device is disconnected
234 * This function also removes the usb class device from the sysfs tree.
236 * This should be called by all drivers that use the USB major number.
238 void usb_deregister_dev(struct usb_interface
*intf
,
239 struct usb_class_driver
*class_driver
)
241 int minor_base
= class_driver
->minor_base
;
244 #ifdef CONFIG_USB_DYNAMIC_MINORS
248 if (intf
->minor
== -1)
251 dbg ("removing %d minor", intf
->minor
);
253 down_write(&minor_rwsem
);
254 usb_minors
[intf
->minor
] = NULL
;
255 up_write(&minor_rwsem
);
257 snprintf(name
, sizeof(name
), class_driver
->name
, intf
->minor
- minor_base
);
258 device_destroy(usb_class
->class, MKDEV(USB_MAJOR
, intf
->minor
));
259 intf
->usb_dev
= NULL
;
263 EXPORT_SYMBOL_GPL(usb_deregister_dev
);
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