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/slab.h>
22 #include <linux/smp_lock.h>
23 #include <linux/usb.h>
27 #define MAX_USB_MINORS 256
28 static const struct file_operations *usb_minors[MAX_USB_MINORS];
29 static DECLARE_RWSEM(minor_rwsem);
31 static int usb_open(struct inode * inode, struct file * file)
33 int minor = iminor(inode);
34 const struct file_operations *c;
36 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);
59 static const struct file_operations usb_fops = {
64 static struct usb_class {
69 static char *usb_devnode(struct device *dev, mode_t *mode)
71 struct usb_class_driver *drv;
73 drv = dev_get_drvdata(dev);
74 if (!drv || !drv->devnode)
76 return drv->devnode(dev, mode);
79 static int init_usb_class(void)
83 if (usb_class != NULL) {
84 kref_get(&usb_class->kref);
88 usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
94 kref_init(&usb_class->kref);
95 usb_class->class = class_create(THIS_MODULE, "usb");
96 if (IS_ERR(usb_class->class)) {
97 result = IS_ERR(usb_class->class);
98 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)
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.
177 if (class_driver->fops == NULL)
179 if (intf->minor >= 0)
182 retval = init_usb_class();
186 dev_dbg(&intf->dev, "looking for a minor, starting at %d", minor_base);
188 down_write(&minor_rwsem);
189 for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
190 if (usb_minors[minor])
193 usb_minors[minor] = class_driver->fops;
197 up_write(&minor_rwsem);
201 /* create a usb class device for this usb interface */
202 snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
203 temp = strrchr(name, '/');
204 if (temp && (temp[1] != '\0'))
208 intf->usb_dev = device_create(usb_class->class, &intf->dev,
209 MKDEV(USB_MAJOR, minor), class_driver,
211 if (IS_ERR(intf->usb_dev)) {
212 down_write(&minor_rwsem);
213 usb_minors[minor] = NULL;
215 up_write(&minor_rwsem);
216 retval = PTR_ERR(intf->usb_dev);
220 EXPORT_SYMBOL_GPL(usb_register_dev);
223 * usb_deregister_dev - deregister a USB device's dynamic minor.
224 * @intf: pointer to the usb_interface that is being deregistered
225 * @class_driver: pointer to the usb_class_driver for this device
227 * Used in conjunction with usb_register_dev(). This function is called
228 * when the USB driver is finished with the minor numbers gotten from a
229 * call to usb_register_dev() (usually when the device is disconnected
232 * This function also removes the usb class device from the sysfs tree.
234 * This should be called by all drivers that use the USB major number.
236 void usb_deregister_dev(struct usb_interface *intf,
237 struct usb_class_driver *class_driver)
239 int minor_base = class_driver->minor_base;
242 #ifdef CONFIG_USB_DYNAMIC_MINORS
246 if (intf->minor == -1)
249 dbg ("removing %d minor", intf->minor);
251 down_write(&minor_rwsem);
252 usb_minors[intf->minor] = NULL;
253 up_write(&minor_rwsem);
255 snprintf(name, sizeof(name), class_driver->name, intf->minor - minor_base);
256 device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
257 intf->usb_dev = NULL;
261 EXPORT_SYMBOL_GPL(usb_deregister_dev);