Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
1da177e4 LT |
20 | #include <linux/spinlock.h> |
21 | #include <linux/errno.h> | |
1da177e4 LT |
22 | #include <linux/usb.h> |
23 | ||
6d5e8254 GK |
24 | #include "usb.h" |
25 | ||
1da177e4 | 26 | #define MAX_USB_MINORS 256 |
99ac48f5 | 27 | static const struct file_operations *usb_minors[MAX_USB_MINORS]; |
1da177e4 LT |
28 | static DEFINE_SPINLOCK(minor_lock); |
29 | ||
30 | static int usb_open(struct inode * inode, struct file * file) | |
31 | { | |
32 | int minor = iminor(inode); | |
99ac48f5 | 33 | const struct file_operations *c; |
1da177e4 | 34 | int err = -ENODEV; |
99ac48f5 | 35 | const struct file_operations *old_fops, *new_fops = NULL; |
1da177e4 LT |
36 | |
37 | spin_lock (&minor_lock); | |
38 | c = usb_minors[minor]; | |
39 | ||
40 | if (!c || !(new_fops = fops_get(c))) { | |
41 | spin_unlock(&minor_lock); | |
42 | return err; | |
43 | } | |
44 | spin_unlock(&minor_lock); | |
45 | ||
46 | old_fops = file->f_op; | |
47 | file->f_op = new_fops; | |
48 | /* Curiouser and curiouser... NULL ->open() as "no device" ? */ | |
49 | if (file->f_op->open) | |
50 | err = file->f_op->open(inode,file); | |
51 | if (err) { | |
52 | fops_put(file->f_op); | |
53 | file->f_op = fops_get(old_fops); | |
54 | } | |
55 | fops_put(old_fops); | |
56 | return err; | |
57 | } | |
58 | ||
59 | static struct file_operations usb_fops = { | |
60 | .owner = THIS_MODULE, | |
61 | .open = usb_open, | |
62 | }; | |
63 | ||
56b22935 | 64 | static struct class *usb_class; |
1da177e4 LT |
65 | |
66 | int usb_major_init(void) | |
67 | { | |
68 | int error; | |
69 | ||
70 | error = register_chrdev(USB_MAJOR, "usb", &usb_fops); | |
71 | if (error) { | |
72 | err("unable to get major %d for usb devices", USB_MAJOR); | |
73 | goto out; | |
74 | } | |
75 | ||
56b22935 | 76 | usb_class = class_create(THIS_MODULE, "usb"); |
1da177e4 | 77 | if (IS_ERR(usb_class)) { |
5cebfb75 | 78 | error = PTR_ERR(usb_class); |
56b22935 | 79 | err("class_create failed for usb devices"); |
1da177e4 LT |
80 | unregister_chrdev(USB_MAJOR, "usb"); |
81 | goto out; | |
82 | } | |
83 | ||
1da177e4 LT |
84 | out: |
85 | return error; | |
86 | } | |
87 | ||
88 | void usb_major_cleanup(void) | |
89 | { | |
56b22935 | 90 | class_destroy(usb_class); |
1da177e4 LT |
91 | unregister_chrdev(USB_MAJOR, "usb"); |
92 | } | |
93 | ||
94 | /** | |
95 | * usb_register_dev - register a USB device, and ask for a minor number | |
96 | * @intf: pointer to the usb_interface that is being registered | |
97 | * @class_driver: pointer to the usb_class_driver for this device | |
98 | * | |
99 | * This should be called by all USB drivers that use the USB major number. | |
100 | * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be | |
101 | * dynamically allocated out of the list of available ones. If it is not | |
102 | * enabled, the minor number will be based on the next available free minor, | |
103 | * starting at the class_driver->minor_base. | |
104 | * | |
d6e5bcf4 | 105 | * This function also creates a usb class device in the sysfs tree. |
1da177e4 LT |
106 | * |
107 | * usb_deregister_dev() must be called when the driver is done with | |
108 | * the minor numbers given out by this function. | |
109 | * | |
110 | * Returns -EINVAL if something bad happens with trying to register a | |
111 | * device, and 0 on success. | |
112 | */ | |
113 | int usb_register_dev(struct usb_interface *intf, | |
114 | struct usb_class_driver *class_driver) | |
115 | { | |
116 | int retval = -EINVAL; | |
117 | int minor_base = class_driver->minor_base; | |
118 | int minor = 0; | |
119 | char name[BUS_ID_SIZE]; | |
120 | char *temp; | |
121 | ||
122 | #ifdef CONFIG_USB_DYNAMIC_MINORS | |
123 | /* | |
124 | * We don't care what the device tries to start at, we want to start | |
125 | * at zero to pack the devices into the smallest available space with | |
126 | * no holes in the minor range. | |
127 | */ | |
128 | minor_base = 0; | |
129 | #endif | |
130 | intf->minor = -1; | |
131 | ||
132 | dbg ("looking for a minor, starting at %d", minor_base); | |
133 | ||
134 | if (class_driver->fops == NULL) | |
135 | goto exit; | |
136 | ||
137 | spin_lock (&minor_lock); | |
138 | for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { | |
139 | if (usb_minors[minor]) | |
140 | continue; | |
141 | ||
142 | usb_minors[minor] = class_driver->fops; | |
143 | ||
144 | retval = 0; | |
145 | break; | |
146 | } | |
147 | spin_unlock (&minor_lock); | |
148 | ||
149 | if (retval) | |
150 | goto exit; | |
151 | ||
152 | intf->minor = minor; | |
153 | ||
1da177e4 | 154 | /* create a usb class device for this usb interface */ |
d6e5bcf4 | 155 | snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base); |
1da177e4 LT |
156 | temp = strrchr(name, '/'); |
157 | if (temp && (temp[1] != 0x00)) | |
158 | ++temp; | |
159 | else | |
160 | temp = name; | |
bd009496 GKH |
161 | intf->usb_dev = device_create(usb_class, &intf->dev, |
162 | MKDEV(USB_MAJOR, minor), "%s", temp); | |
163 | if (IS_ERR(intf->usb_dev)) { | |
1da177e4 LT |
164 | spin_lock (&minor_lock); |
165 | usb_minors[intf->minor] = NULL; | |
166 | spin_unlock (&minor_lock); | |
bd009496 | 167 | retval = PTR_ERR(intf->usb_dev); |
1da177e4 LT |
168 | } |
169 | exit: | |
170 | return retval; | |
171 | } | |
172 | EXPORT_SYMBOL(usb_register_dev); | |
173 | ||
174 | /** | |
175 | * usb_deregister_dev - deregister a USB device's dynamic minor. | |
176 | * @intf: pointer to the usb_interface that is being deregistered | |
177 | * @class_driver: pointer to the usb_class_driver for this device | |
178 | * | |
179 | * Used in conjunction with usb_register_dev(). This function is called | |
180 | * when the USB driver is finished with the minor numbers gotten from a | |
181 | * call to usb_register_dev() (usually when the device is disconnected | |
182 | * from the system.) | |
183 | * | |
d6e5bcf4 GKH |
184 | * This function also removes the usb class device from the sysfs tree. |
185 | * | |
1da177e4 LT |
186 | * This should be called by all drivers that use the USB major number. |
187 | */ | |
188 | void usb_deregister_dev(struct usb_interface *intf, | |
189 | struct usb_class_driver *class_driver) | |
190 | { | |
191 | int minor_base = class_driver->minor_base; | |
192 | char name[BUS_ID_SIZE]; | |
193 | ||
194 | #ifdef CONFIG_USB_DYNAMIC_MINORS | |
195 | minor_base = 0; | |
196 | #endif | |
197 | ||
198 | if (intf->minor == -1) | |
199 | return; | |
200 | ||
201 | dbg ("removing %d minor", intf->minor); | |
202 | ||
203 | spin_lock (&minor_lock); | |
204 | usb_minors[intf->minor] = NULL; | |
205 | spin_unlock (&minor_lock); | |
206 | ||
207 | snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); | |
bd009496 GKH |
208 | device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor)); |
209 | intf->usb_dev = NULL; | |
1da177e4 LT |
210 | intf->minor = -1; |
211 | } | |
212 | EXPORT_SYMBOL(usb_deregister_dev); | |
213 | ||
214 |