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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * drivers/usb/core/file.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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,
11 more docs, etc)
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
15 *
16 */
17
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/errno.h>
Alan Sternd4ead162007-05-22 11:46:41 -040020#include <linux/rwsem.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/usb.h>
23
Greg KH6d5e8252005-04-18 17:39:24 -070024#include "usb.h"
25
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#define MAX_USB_MINORS 256
Arjan van de Ven99ac48f2006-03-28 01:56:41 -080027static const struct file_operations *usb_minors[MAX_USB_MINORS];
Alan Sternd4ead162007-05-22 11:46:41 -040028static DECLARE_RWSEM(minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30static int usb_open(struct inode * inode, struct file * file)
31{
32 int minor = iminor(inode);
Arjan van de Ven99ac48f2006-03-28 01:56:41 -080033 const struct file_operations *c;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 int err = -ENODEV;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -080035 const struct file_operations *old_fops, *new_fops = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Alan Sternd4ead162007-05-22 11:46:41 -040037 down_read(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 c = usb_minors[minor];
39
Alan Sternd4ead162007-05-22 11:46:41 -040040 if (!c || !(new_fops = fops_get(c)))
41 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43 old_fops = file->f_op;
44 file->f_op = new_fops;
45 /* Curiouser and curiouser... NULL ->open() as "no device" ? */
46 if (file->f_op->open)
47 err = file->f_op->open(inode,file);
48 if (err) {
49 fops_put(file->f_op);
50 file->f_op = fops_get(old_fops);
51 }
52 fops_put(old_fops);
Alan Sternd4ead162007-05-22 11:46:41 -040053 done:
54 up_read(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 return err;
56}
57
Luiz Fernando N. Capitulino066202d2006-08-05 20:37:11 -030058static const struct file_operations usb_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 .owner = THIS_MODULE,
60 .open = usb_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +020061 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070062};
63
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070064static struct usb_class {
65 struct kref kref;
66 struct class *class;
67} *usb_class;
68
Kay Sieverse454cea2009-09-18 23:01:12 +020069static char *usb_devnode(struct device *dev, mode_t *mode)
Kay Sieversf7a386c2009-04-30 15:23:42 +020070{
71 struct usb_class_driver *drv;
72
73 drv = dev_get_drvdata(dev);
Kay Sieverse454cea2009-09-18 23:01:12 +020074 if (!drv || !drv->devnode)
Kay Sieversf7a386c2009-04-30 15:23:42 +020075 return NULL;
Kay Sieverse454cea2009-09-18 23:01:12 +020076 return drv->devnode(dev, mode);
Kay Sieversf7a386c2009-04-30 15:23:42 +020077}
78
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070079static int init_usb_class(void)
80{
81 int result = 0;
82
83 if (usb_class != NULL) {
84 kref_get(&usb_class->kref);
85 goto exit;
86 }
87
88 usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
89 if (!usb_class) {
90 result = -ENOMEM;
91 goto exit;
92 }
93
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);
Greg Kroah-Hartman69a85942008-08-14 09:37:34 -070098 printk(KERN_ERR "class_create failed for usb devices\n");
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070099 kfree(usb_class);
100 usb_class = NULL;
Dan Carpentered7487c2009-11-10 11:02:08 +0200101 goto exit;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700102 }
Kay Sieverse454cea2009-09-18 23:01:12 +0200103 usb_class->class->devnode = usb_devnode;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700104
105exit:
106 return result;
107}
108
109static void release_usb_class(struct kref *kref)
110{
111 /* Ok, we cheat as we know we only have one usb_class */
112 class_destroy(usb_class->class);
113 kfree(usb_class);
114 usb_class = NULL;
115}
116
117static void destroy_usb_class(void)
118{
119 if (usb_class)
120 kref_put(&usb_class->kref, release_usb_class);
121}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123int usb_major_init(void)
124{
125 int error;
126
127 error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700128 if (error)
Greg Kroah-Hartman69a85942008-08-14 09:37:34 -0700129 printk(KERN_ERR "Unable to get major %d for usb devices\n",
130 USB_MAJOR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 return error;
133}
134
135void usb_major_cleanup(void)
136{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 unregister_chrdev(USB_MAJOR, "usb");
138}
139
140/**
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
144 *
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.
150 *
Greg Kroah-Hartmand6e5bcf2005-06-20 21:15:16 -0700151 * This function also creates a usb class device in the sysfs tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 *
153 * usb_deregister_dev() must be called when the driver is done with
154 * the minor numbers given out by this function.
155 *
156 * Returns -EINVAL if something bad happens with trying to register a
157 * device, and 0 on success.
158 */
159int usb_register_dev(struct usb_interface *intf,
160 struct usb_class_driver *class_driver)
161{
Alan Stern0026e002010-09-21 15:01:53 -0400162 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 int minor_base = class_driver->minor_base;
Alan Stern0026e002010-09-21 15:01:53 -0400164 int minor;
Kay Sievers7071a3c2008-05-02 06:02:41 +0200165 char name[20];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 char *temp;
167
168#ifdef CONFIG_USB_DYNAMIC_MINORS
169 /*
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.
173 */
174 minor_base = 0;
175#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177 if (class_driver->fops == NULL)
Alan Stern0026e002010-09-21 15:01:53 -0400178 return -EINVAL;
179 if (intf->minor >= 0)
180 return -EADDRINUSE;
181
182 retval = init_usb_class();
183 if (retval)
184 return retval;
185
186 dev_dbg(&intf->dev, "looking for a minor, starting at %d", minor_base);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Alan Sternd4ead162007-05-22 11:46:41 -0400188 down_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
190 if (usb_minors[minor])
191 continue;
192
193 usb_minors[minor] = class_driver->fops;
Alan Stern0026e002010-09-21 15:01:53 -0400194 intf->minor = minor;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 break;
196 }
Alan Sternd4ead162007-05-22 11:46:41 -0400197 up_write(&minor_rwsem);
Alan Stern0026e002010-09-21 15:01:53 -0400198 if (intf->minor < 0)
199 return -EXFULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 /* create a usb class device for this usb interface */
Kay Sievers7071a3c2008-05-02 06:02:41 +0200202 snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 temp = strrchr(name, '/');
Kay Sievers7071a3c2008-05-02 06:02:41 +0200204 if (temp && (temp[1] != '\0'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 ++temp;
206 else
207 temp = name;
Greg Kroah-Hartmanb0b090e2008-07-21 20:03:34 -0700208 intf->usb_dev = device_create(usb_class->class, &intf->dev,
Kay Sieversf7a386c2009-04-30 15:23:42 +0200209 MKDEV(USB_MAJOR, minor), class_driver,
Greg Kroah-Hartmanb0b090e2008-07-21 20:03:34 -0700210 "%s", temp);
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700211 if (IS_ERR(intf->usb_dev)) {
Alan Sternd4ead162007-05-22 11:46:41 -0400212 down_write(&minor_rwsem);
Alan Stern0026e002010-09-21 15:01:53 -0400213 usb_minors[minor] = NULL;
214 intf->minor = -1;
Alan Sternd4ead162007-05-22 11:46:41 -0400215 up_write(&minor_rwsem);
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700216 retval = PTR_ERR(intf->usb_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 return retval;
219}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600220EXPORT_SYMBOL_GPL(usb_register_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
222/**
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
226 *
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
230 * from the system.)
231 *
Greg Kroah-Hartmand6e5bcf2005-06-20 21:15:16 -0700232 * This function also removes the usb class device from the sysfs tree.
233 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 * This should be called by all drivers that use the USB major number.
235 */
236void usb_deregister_dev(struct usb_interface *intf,
237 struct usb_class_driver *class_driver)
238{
239 int minor_base = class_driver->minor_base;
Kay Sievers7071a3c2008-05-02 06:02:41 +0200240 char name[20];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
242#ifdef CONFIG_USB_DYNAMIC_MINORS
243 minor_base = 0;
244#endif
245
246 if (intf->minor == -1)
247 return;
248
249 dbg ("removing %d minor", intf->minor);
250
Alan Sternd4ead162007-05-22 11:46:41 -0400251 down_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 usb_minors[intf->minor] = NULL;
Alan Sternd4ead162007-05-22 11:46:41 -0400253 up_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Kay Sievers7071a3c2008-05-02 06:02:41 +0200255 snprintf(name, sizeof(name), class_driver->name, intf->minor - minor_base);
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700256 device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
257 intf->usb_dev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 intf->minor = -1;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700259 destroy_usb_class();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600261EXPORT_SYMBOL_GPL(usb_deregister_dev);