blob: 80ce9644d0eea027546f55cba42d921fb7e57aeb [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * drivers/usb/file.c
3 *
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
18#include <linux/config.h>
19#include <linux/module.h>
20#include <linux/devfs_fs_kernel.h>
21#include <linux/spinlock.h>
22#include <linux/errno.h>
23
24#ifdef CONFIG_USB_DEBUG
25 #define DEBUG
26#else
27 #undef DEBUG
28#endif
29#include <linux/usb.h>
30
31#define MAX_USB_MINORS 256
32static struct file_operations *usb_minors[MAX_USB_MINORS];
33static DEFINE_SPINLOCK(minor_lock);
34
35static int usb_open(struct inode * inode, struct file * file)
36{
37 int minor = iminor(inode);
38 struct file_operations *c;
39 int err = -ENODEV;
40 struct file_operations *old_fops, *new_fops = NULL;
41
42 spin_lock (&minor_lock);
43 c = usb_minors[minor];
44
45 if (!c || !(new_fops = fops_get(c))) {
46 spin_unlock(&minor_lock);
47 return err;
48 }
49 spin_unlock(&minor_lock);
50
51 old_fops = file->f_op;
52 file->f_op = new_fops;
53 /* Curiouser and curiouser... NULL ->open() as "no device" ? */
54 if (file->f_op->open)
55 err = file->f_op->open(inode,file);
56 if (err) {
57 fops_put(file->f_op);
58 file->f_op = fops_get(old_fops);
59 }
60 fops_put(old_fops);
61 return err;
62}
63
64static struct file_operations usb_fops = {
65 .owner = THIS_MODULE,
66 .open = usb_open,
67};
68
69static struct class_simple *usb_class;
70
71int usb_major_init(void)
72{
73 int error;
74
75 error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
76 if (error) {
77 err("unable to get major %d for usb devices", USB_MAJOR);
78 goto out;
79 }
80
81 usb_class = class_simple_create(THIS_MODULE, "usb");
82 if (IS_ERR(usb_class)) {
83 err("class_simple_create failed for usb devices");
84 unregister_chrdev(USB_MAJOR, "usb");
85 goto out;
86 }
87
88 devfs_mk_dir("usb");
89
90out:
91 return error;
92}
93
94void usb_major_cleanup(void)
95{
96 class_simple_destroy(usb_class);
97 devfs_remove("usb");
98 unregister_chrdev(USB_MAJOR, "usb");
99}
100
101/**
102 * usb_register_dev - register a USB device, and ask for a minor number
103 * @intf: pointer to the usb_interface that is being registered
104 * @class_driver: pointer to the usb_class_driver for this device
105 *
106 * This should be called by all USB drivers that use the USB major number.
107 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
108 * dynamically allocated out of the list of available ones. If it is not
109 * enabled, the minor number will be based on the next available free minor,
110 * starting at the class_driver->minor_base.
111 *
112 * This function also creates the devfs file for the usb device, if devfs
113 * is enabled, and creates a usb class device in the sysfs tree.
114 *
115 * usb_deregister_dev() must be called when the driver is done with
116 * the minor numbers given out by this function.
117 *
118 * Returns -EINVAL if something bad happens with trying to register a
119 * device, and 0 on success.
120 */
121int usb_register_dev(struct usb_interface *intf,
122 struct usb_class_driver *class_driver)
123{
124 int retval = -EINVAL;
125 int minor_base = class_driver->minor_base;
126 int minor = 0;
127 char name[BUS_ID_SIZE];
128 char *temp;
129
130#ifdef CONFIG_USB_DYNAMIC_MINORS
131 /*
132 * We don't care what the device tries to start at, we want to start
133 * at zero to pack the devices into the smallest available space with
134 * no holes in the minor range.
135 */
136 minor_base = 0;
137#endif
138 intf->minor = -1;
139
140 dbg ("looking for a minor, starting at %d", minor_base);
141
142 if (class_driver->fops == NULL)
143 goto exit;
144
145 spin_lock (&minor_lock);
146 for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
147 if (usb_minors[minor])
148 continue;
149
150 usb_minors[minor] = class_driver->fops;
151
152 retval = 0;
153 break;
154 }
155 spin_unlock (&minor_lock);
156
157 if (retval)
158 goto exit;
159
160 intf->minor = minor;
161
162 /* handle the devfs registration */
163 snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
164 devfs_mk_cdev(MKDEV(USB_MAJOR, minor), class_driver->mode, name);
165
166 /* create a usb class device for this usb interface */
167 temp = strrchr(name, '/');
168 if (temp && (temp[1] != 0x00))
169 ++temp;
170 else
171 temp = name;
172 intf->class_dev = class_simple_device_add(usb_class, MKDEV(USB_MAJOR, minor), &intf->dev, "%s", temp);
173 if (IS_ERR(intf->class_dev)) {
174 spin_lock (&minor_lock);
175 usb_minors[intf->minor] = NULL;
176 spin_unlock (&minor_lock);
177 devfs_remove (name);
178 retval = PTR_ERR(intf->class_dev);
179 }
180exit:
181 return retval;
182}
183EXPORT_SYMBOL(usb_register_dev);
184
185/**
186 * usb_deregister_dev - deregister a USB device's dynamic minor.
187 * @intf: pointer to the usb_interface that is being deregistered
188 * @class_driver: pointer to the usb_class_driver for this device
189 *
190 * Used in conjunction with usb_register_dev(). This function is called
191 * when the USB driver is finished with the minor numbers gotten from a
192 * call to usb_register_dev() (usually when the device is disconnected
193 * from the system.)
194 *
195 * This function also cleans up the devfs file for the usb device, if devfs
196 * is enabled, and removes the usb class device from the sysfs tree.
197 *
198 * This should be called by all drivers that use the USB major number.
199 */
200void usb_deregister_dev(struct usb_interface *intf,
201 struct usb_class_driver *class_driver)
202{
203 int minor_base = class_driver->minor_base;
204 char name[BUS_ID_SIZE];
205
206#ifdef CONFIG_USB_DYNAMIC_MINORS
207 minor_base = 0;
208#endif
209
210 if (intf->minor == -1)
211 return;
212
213 dbg ("removing %d minor", intf->minor);
214
215 spin_lock (&minor_lock);
216 usb_minors[intf->minor] = NULL;
217 spin_unlock (&minor_lock);
218
219 snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
220 devfs_remove (name);
221 class_simple_device_remove(MKDEV(USB_MAJOR, intf->minor));
222 intf->class_dev = NULL;
223 intf->minor = -1;
224}
225EXPORT_SYMBOL(usb_deregister_dev);
226
227