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Commit | Line | Data |
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1da177e4 | 1 | /* |
f30c2269 | 2 | * drivers/usb/core/file.c |
1da177e4 LT |
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 | ||
1da177e4 | 18 | #include <linux/module.h> |
1da177e4 | 19 | #include <linux/errno.h> |
d4ead16f | 20 | #include <linux/rwsem.h> |
1da177e4 LT |
21 | #include <linux/usb.h> |
22 | ||
6d5e8254 GKH |
23 | #include "usb.h" |
24 | ||
1da177e4 | 25 | #define MAX_USB_MINORS 256 |
99ac48f5 | 26 | static const struct file_operations *usb_minors[MAX_USB_MINORS]; |
d4ead16f | 27 | static DECLARE_RWSEM(minor_rwsem); |
1da177e4 LT |
28 | |
29 | static int usb_open(struct inode * inode, struct file * file) | |
30 | { | |
31 | int minor = iminor(inode); | |
99ac48f5 | 32 | const struct file_operations *c; |
1da177e4 | 33 | int err = -ENODEV; |
99ac48f5 | 34 | const struct file_operations *old_fops, *new_fops = NULL; |
1da177e4 | 35 | |
d4ead16f | 36 | down_read(&minor_rwsem); |
1da177e4 LT |
37 | c = usb_minors[minor]; |
38 | ||
d4ead16f AS |
39 | if (!c || !(new_fops = fops_get(c))) |
40 | goto done; | |
1da177e4 LT |
41 | |
42 | old_fops = file->f_op; | |
43 | file->f_op = new_fops; | |
44 | /* Curiouser and curiouser... NULL ->open() as "no device" ? */ | |
45 | if (file->f_op->open) | |
46 | err = file->f_op->open(inode,file); | |
47 | if (err) { | |
48 | fops_put(file->f_op); | |
49 | file->f_op = fops_get(old_fops); | |
50 | } | |
51 | fops_put(old_fops); | |
d4ead16f AS |
52 | done: |
53 | up_read(&minor_rwsem); | |
1da177e4 LT |
54 | return err; |
55 | } | |
56 | ||
066202dd | 57 | static const struct file_operations usb_fops = { |
1da177e4 LT |
58 | .owner = THIS_MODULE, |
59 | .open = usb_open, | |
60 | }; | |
61 | ||
43104f1d GKH |
62 | static struct usb_class { |
63 | struct kref kref; | |
64 | struct class *class; | |
65 | } *usb_class; | |
1da177e4 | 66 | |
43104f1d | 67 | static int init_usb_class(void) |
1da177e4 | 68 | { |
43104f1d | 69 | int result = 0; |
1da177e4 | 70 | |
43104f1d GKH |
71 | if (usb_class != NULL) { |
72 | kref_get(&usb_class->kref); | |
73 | goto exit; | |
74 | } | |
75 | ||
76 | usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); | |
77 | if (!usb_class) { | |
78 | result = -ENOMEM; | |
79 | goto exit; | |
1da177e4 LT |
80 | } |
81 | ||
43104f1d GKH |
82 | kref_init(&usb_class->kref); |
83 | usb_class->class = class_create(THIS_MODULE, "usb"); | |
84 | if (IS_ERR(usb_class->class)) { | |
85 | result = IS_ERR(usb_class->class); | |
56b22935 | 86 | err("class_create failed for usb devices"); |
43104f1d GKH |
87 | kfree(usb_class); |
88 | usb_class = NULL; | |
1da177e4 LT |
89 | } |
90 | ||
43104f1d GKH |
91 | exit: |
92 | return result; | |
93 | } | |
94 | ||
95 | static void release_usb_class(struct kref *kref) | |
96 | { | |
97 | /* Ok, we cheat as we know we only have one usb_class */ | |
98 | class_destroy(usb_class->class); | |
99 | kfree(usb_class); | |
100 | usb_class = NULL; | |
101 | } | |
102 | ||
103 | static void destroy_usb_class(void) | |
104 | { | |
105 | if (usb_class) | |
106 | kref_put(&usb_class->kref, release_usb_class); | |
107 | } | |
108 | ||
109 | int usb_major_init(void) | |
110 | { | |
111 | int error; | |
112 | ||
113 | error = register_chrdev(USB_MAJOR, "usb", &usb_fops); | |
114 | if (error) | |
115 | err("unable to get major %d for usb devices", USB_MAJOR); | |
116 | ||
1da177e4 LT |
117 | return error; |
118 | } | |
119 | ||
120 | void usb_major_cleanup(void) | |
121 | { | |
1da177e4 LT |
122 | unregister_chrdev(USB_MAJOR, "usb"); |
123 | } | |
124 | ||
125 | /** | |
126 | * usb_register_dev - register a USB device, and ask for a minor number | |
127 | * @intf: pointer to the usb_interface that is being registered | |
128 | * @class_driver: pointer to the usb_class_driver for this device | |
129 | * | |
130 | * This should be called by all USB drivers that use the USB major number. | |
131 | * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be | |
132 | * dynamically allocated out of the list of available ones. If it is not | |
133 | * enabled, the minor number will be based on the next available free minor, | |
134 | * starting at the class_driver->minor_base. | |
135 | * | |
d6e5bcf4 | 136 | * This function also creates a usb class device in the sysfs tree. |
1da177e4 LT |
137 | * |
138 | * usb_deregister_dev() must be called when the driver is done with | |
139 | * the minor numbers given out by this function. | |
140 | * | |
141 | * Returns -EINVAL if something bad happens with trying to register a | |
142 | * device, and 0 on success. | |
143 | */ | |
144 | int usb_register_dev(struct usb_interface *intf, | |
145 | struct usb_class_driver *class_driver) | |
146 | { | |
147 | int retval = -EINVAL; | |
148 | int minor_base = class_driver->minor_base; | |
149 | int minor = 0; | |
150 | char name[BUS_ID_SIZE]; | |
151 | char *temp; | |
152 | ||
153 | #ifdef CONFIG_USB_DYNAMIC_MINORS | |
154 | /* | |
155 | * We don't care what the device tries to start at, we want to start | |
156 | * at zero to pack the devices into the smallest available space with | |
157 | * no holes in the minor range. | |
158 | */ | |
159 | minor_base = 0; | |
160 | #endif | |
161 | intf->minor = -1; | |
162 | ||
163 | dbg ("looking for a minor, starting at %d", minor_base); | |
164 | ||
165 | if (class_driver->fops == NULL) | |
166 | goto exit; | |
167 | ||
d4ead16f | 168 | down_write(&minor_rwsem); |
1da177e4 LT |
169 | for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { |
170 | if (usb_minors[minor]) | |
171 | continue; | |
172 | ||
173 | usb_minors[minor] = class_driver->fops; | |
174 | ||
175 | retval = 0; | |
176 | break; | |
177 | } | |
d4ead16f | 178 | up_write(&minor_rwsem); |
1da177e4 | 179 | |
43104f1d GKH |
180 | if (retval) |
181 | goto exit; | |
182 | ||
183 | retval = init_usb_class(); | |
1da177e4 LT |
184 | if (retval) |
185 | goto exit; | |
186 | ||
187 | intf->minor = minor; | |
188 | ||
1da177e4 | 189 | /* create a usb class device for this usb interface */ |
d6e5bcf4 | 190 | snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base); |
1da177e4 LT |
191 | temp = strrchr(name, '/'); |
192 | if (temp && (temp[1] != 0x00)) | |
193 | ++temp; | |
194 | else | |
195 | temp = name; | |
0873c764 GKH |
196 | intf->usb_dev = device_create(usb_class->class, &intf->dev, |
197 | MKDEV(USB_MAJOR, minor), "%s", temp); | |
198 | if (IS_ERR(intf->usb_dev)) { | |
d4ead16f | 199 | down_write(&minor_rwsem); |
1da177e4 | 200 | usb_minors[intf->minor] = NULL; |
d4ead16f | 201 | up_write(&minor_rwsem); |
0873c764 | 202 | retval = PTR_ERR(intf->usb_dev); |
1da177e4 LT |
203 | } |
204 | exit: | |
205 | return retval; | |
206 | } | |
782e70c6 | 207 | EXPORT_SYMBOL_GPL(usb_register_dev); |
1da177e4 LT |
208 | |
209 | /** | |
210 | * usb_deregister_dev - deregister a USB device's dynamic minor. | |
211 | * @intf: pointer to the usb_interface that is being deregistered | |
212 | * @class_driver: pointer to the usb_class_driver for this device | |
213 | * | |
214 | * Used in conjunction with usb_register_dev(). This function is called | |
215 | * when the USB driver is finished with the minor numbers gotten from a | |
216 | * call to usb_register_dev() (usually when the device is disconnected | |
217 | * from the system.) | |
218 | * | |
d6e5bcf4 GKH |
219 | * This function also removes the usb class device from the sysfs tree. |
220 | * | |
1da177e4 LT |
221 | * This should be called by all drivers that use the USB major number. |
222 | */ | |
223 | void usb_deregister_dev(struct usb_interface *intf, | |
224 | struct usb_class_driver *class_driver) | |
225 | { | |
226 | int minor_base = class_driver->minor_base; | |
227 | char name[BUS_ID_SIZE]; | |
228 | ||
229 | #ifdef CONFIG_USB_DYNAMIC_MINORS | |
230 | minor_base = 0; | |
231 | #endif | |
232 | ||
233 | if (intf->minor == -1) | |
234 | return; | |
235 | ||
236 | dbg ("removing %d minor", intf->minor); | |
237 | ||
d4ead16f | 238 | down_write(&minor_rwsem); |
1da177e4 | 239 | usb_minors[intf->minor] = NULL; |
d4ead16f | 240 | up_write(&minor_rwsem); |
1da177e4 LT |
241 | |
242 | snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); | |
0873c764 GKH |
243 | device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); |
244 | intf->usb_dev = NULL; | |
1da177e4 | 245 | intf->minor = -1; |
43104f1d | 246 | destroy_usb_class(); |
1da177e4 | 247 | } |
782e70c6 | 248 | EXPORT_SYMBOL_GPL(usb_deregister_dev); |