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
;
38 down_read(&minor_rwsem
);
39 c
= usb_minors
[minor
];
41 if (!c
|| !(new_fops
= fops_get(c
)))
44 old_fops
= file
->f_op
;
45 file
->f_op
= new_fops
;
46 /* Curiouser and curiouser... NULL ->open() as "no device" ? */
48 err
= file
->f_op
->open(inode
,file
);
51 file
->f_op
= fops_get(old_fops
);
55 up_read(&minor_rwsem
);
60 static const struct file_operations usb_fops
= {
65 static struct usb_class
{
70 static char *usb_devnode(struct device
*dev
, mode_t
*mode
)
72 struct usb_class_driver
*drv
;
74 drv
= dev_get_drvdata(dev
);
75 if (!drv
|| !drv
->devnode
)
77 return drv
->devnode(dev
, mode
);
80 static int init_usb_class(void)
84 if (usb_class
!= NULL
) {
85 kref_get(&usb_class
->kref
);
89 usb_class
= kmalloc(sizeof(*usb_class
), GFP_KERNEL
);
95 kref_init(&usb_class
->kref
);
96 usb_class
->class = class_create(THIS_MODULE
, "usb");
97 if (IS_ERR(usb_class
->class)) {
98 result
= IS_ERR(usb_class
->class);
99 printk(KERN_ERR
"class_create failed for usb devices\n");
103 usb_class
->class->devnode
= usb_devnode
;
109 static void release_usb_class(struct kref
*kref
)
111 /* Ok, we cheat as we know we only have one usb_class */
112 class_destroy(usb_class
->class);
117 static void destroy_usb_class(void)
120 kref_put(&usb_class
->kref
, release_usb_class
);
123 int usb_major_init(void)
127 error
= register_chrdev(USB_MAJOR
, "usb", &usb_fops
);
129 printk(KERN_ERR
"Unable to get major %d for usb devices\n",
135 void usb_major_cleanup(void)
137 unregister_chrdev(USB_MAJOR
, "usb");
141 * usb_register_dev - register a USB device, and ask for a minor number
142 * @intf: pointer to the usb_interface that is being registered
143 * @class_driver: pointer to the usb_class_driver for this device
145 * This should be called by all USB drivers that use the USB major number.
146 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
147 * dynamically allocated out of the list of available ones. If it is not
148 * enabled, the minor number will be based on the next available free minor,
149 * starting at the class_driver->minor_base.
151 * This function also creates a usb class device in the sysfs tree.
153 * usb_deregister_dev() must be called when the driver is done with
154 * the minor numbers given out by this function.
156 * Returns -EINVAL if something bad happens with trying to register a
157 * device, and 0 on success.
159 int usb_register_dev(struct usb_interface
*intf
,
160 struct usb_class_driver
*class_driver
)
162 int retval
= -EINVAL
;
163 int minor_base
= class_driver
->minor_base
;
168 #ifdef CONFIG_USB_DYNAMIC_MINORS
170 * We don't care what the device tries to start at, we want to start
171 * at zero to pack the devices into the smallest available space with
172 * no holes in the minor range.
178 dbg ("looking for a minor, starting at %d", minor_base
);
180 if (class_driver
->fops
== NULL
)
183 down_write(&minor_rwsem
);
184 for (minor
= minor_base
; minor
< MAX_USB_MINORS
; ++minor
) {
185 if (usb_minors
[minor
])
188 usb_minors
[minor
] = class_driver
->fops
;
193 up_write(&minor_rwsem
);
198 retval
= init_usb_class();
204 /* create a usb class device for this usb interface */
205 snprintf(name
, sizeof(name
), class_driver
->name
, minor
- minor_base
);
206 temp
= strrchr(name
, '/');
207 if (temp
&& (temp
[1] != '\0'))
211 intf
->usb_dev
= device_create(usb_class
->class, &intf
->dev
,
212 MKDEV(USB_MAJOR
, minor
), class_driver
,
214 if (IS_ERR(intf
->usb_dev
)) {
215 down_write(&minor_rwsem
);
216 usb_minors
[intf
->minor
] = NULL
;
217 up_write(&minor_rwsem
);
218 retval
= PTR_ERR(intf
->usb_dev
);
223 EXPORT_SYMBOL_GPL(usb_register_dev
);
226 * usb_deregister_dev - deregister a USB device's dynamic minor.
227 * @intf: pointer to the usb_interface that is being deregistered
228 * @class_driver: pointer to the usb_class_driver for this device
230 * Used in conjunction with usb_register_dev(). This function is called
231 * when the USB driver is finished with the minor numbers gotten from a
232 * call to usb_register_dev() (usually when the device is disconnected
235 * This function also removes the usb class device from the sysfs tree.
237 * This should be called by all drivers that use the USB major number.
239 void usb_deregister_dev(struct usb_interface
*intf
,
240 struct usb_class_driver
*class_driver
)
242 int minor_base
= class_driver
->minor_base
;
245 #ifdef CONFIG_USB_DYNAMIC_MINORS
249 if (intf
->minor
== -1)
252 dbg ("removing %d minor", intf
->minor
);
254 down_write(&minor_rwsem
);
255 usb_minors
[intf
->minor
] = NULL
;
256 up_write(&minor_rwsem
);
258 snprintf(name
, sizeof(name
), class_driver
->name
, intf
->minor
- minor_base
);
259 device_destroy(usb_class
->class, MKDEV(USB_MAJOR
, intf
->minor
));
260 intf
->usb_dev
= NULL
;
264 EXPORT_SYMBOL_GPL(usb_deregister_dev
);
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