iwlwifi: don't include iwl-dev.h from iwl-devtrace.h
[deliverable/linux.git] / drivers / usb / core / file.c
1 /*
2 * drivers/usb/core/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/module.h>
19 #include <linux/errno.h>
20 #include <linux/rwsem.h>
21 #include <linux/smp_lock.h>
22 #include <linux/usb.h>
23
24 #include "usb.h"
25
26 #define MAX_USB_MINORS 256
27 static const struct file_operations *usb_minors[MAX_USB_MINORS];
28 static DECLARE_RWSEM(minor_rwsem);
29
30 static int usb_open(struct inode * inode, struct file * file)
31 {
32 int minor = iminor(inode);
33 const struct file_operations *c;
34 int err = -ENODEV;
35 const struct file_operations *old_fops, *new_fops = NULL;
36
37 down_read(&minor_rwsem);
38 c = usb_minors[minor];
39
40 if (!c || !(new_fops = fops_get(c)))
41 goto done;
42
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);
53 done:
54 up_read(&minor_rwsem);
55 return err;
56 }
57
58 static const struct file_operations usb_fops = {
59 .owner = THIS_MODULE,
60 .open = usb_open,
61 };
62
63 static struct usb_class {
64 struct kref kref;
65 struct class *class;
66 } *usb_class;
67
68 static char *usb_devnode(struct device *dev, mode_t *mode)
69 {
70 struct usb_class_driver *drv;
71
72 drv = dev_get_drvdata(dev);
73 if (!drv || !drv->devnode)
74 return NULL;
75 return drv->devnode(dev, mode);
76 }
77
78 static int init_usb_class(void)
79 {
80 int result = 0;
81
82 if (usb_class != NULL) {
83 kref_get(&usb_class->kref);
84 goto exit;
85 }
86
87 usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
88 if (!usb_class) {
89 result = -ENOMEM;
90 goto exit;
91 }
92
93 kref_init(&usb_class->kref);
94 usb_class->class = class_create(THIS_MODULE, "usb");
95 if (IS_ERR(usb_class->class)) {
96 result = IS_ERR(usb_class->class);
97 printk(KERN_ERR "class_create failed for usb devices\n");
98 kfree(usb_class);
99 usb_class = NULL;
100 goto exit;
101 }
102 usb_class->class->devnode = usb_devnode;
103
104 exit:
105 return result;
106 }
107
108 static void release_usb_class(struct kref *kref)
109 {
110 /* Ok, we cheat as we know we only have one usb_class */
111 class_destroy(usb_class->class);
112 kfree(usb_class);
113 usb_class = NULL;
114 }
115
116 static void destroy_usb_class(void)
117 {
118 if (usb_class)
119 kref_put(&usb_class->kref, release_usb_class);
120 }
121
122 int usb_major_init(void)
123 {
124 int error;
125
126 error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
127 if (error)
128 printk(KERN_ERR "Unable to get major %d for usb devices\n",
129 USB_MAJOR);
130
131 return error;
132 }
133
134 void usb_major_cleanup(void)
135 {
136 unregister_chrdev(USB_MAJOR, "usb");
137 }
138
139 /**
140 * usb_register_dev - register a USB device, and ask for a minor number
141 * @intf: pointer to the usb_interface that is being registered
142 * @class_driver: pointer to the usb_class_driver for this device
143 *
144 * This should be called by all USB drivers that use the USB major number.
145 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
146 * dynamically allocated out of the list of available ones. If it is not
147 * enabled, the minor number will be based on the next available free minor,
148 * starting at the class_driver->minor_base.
149 *
150 * This function also creates a usb class device in the sysfs tree.
151 *
152 * usb_deregister_dev() must be called when the driver is done with
153 * the minor numbers given out by this function.
154 *
155 * Returns -EINVAL if something bad happens with trying to register a
156 * device, and 0 on success.
157 */
158 int usb_register_dev(struct usb_interface *intf,
159 struct usb_class_driver *class_driver)
160 {
161 int retval = -EINVAL;
162 int minor_base = class_driver->minor_base;
163 int minor = 0;
164 char name[20];
165 char *temp;
166
167 #ifdef CONFIG_USB_DYNAMIC_MINORS
168 /*
169 * We don't care what the device tries to start at, we want to start
170 * at zero to pack the devices into the smallest available space with
171 * no holes in the minor range.
172 */
173 minor_base = 0;
174 #endif
175 intf->minor = -1;
176
177 dbg ("looking for a minor, starting at %d", minor_base);
178
179 if (class_driver->fops == NULL)
180 goto exit;
181
182 down_write(&minor_rwsem);
183 for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
184 if (usb_minors[minor])
185 continue;
186
187 usb_minors[minor] = class_driver->fops;
188
189 retval = 0;
190 break;
191 }
192 up_write(&minor_rwsem);
193
194 if (retval)
195 goto exit;
196
197 retval = init_usb_class();
198 if (retval)
199 goto exit;
200
201 intf->minor = minor;
202
203 /* create a usb class device for this usb interface */
204 snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
205 temp = strrchr(name, '/');
206 if (temp && (temp[1] != '\0'))
207 ++temp;
208 else
209 temp = name;
210 intf->usb_dev = device_create(usb_class->class, &intf->dev,
211 MKDEV(USB_MAJOR, minor), class_driver,
212 "%s", temp);
213 if (IS_ERR(intf->usb_dev)) {
214 down_write(&minor_rwsem);
215 usb_minors[intf->minor] = NULL;
216 up_write(&minor_rwsem);
217 retval = PTR_ERR(intf->usb_dev);
218 }
219 exit:
220 return retval;
221 }
222 EXPORT_SYMBOL_GPL(usb_register_dev);
223
224 /**
225 * usb_deregister_dev - deregister a USB device's dynamic minor.
226 * @intf: pointer to the usb_interface that is being deregistered
227 * @class_driver: pointer to the usb_class_driver for this device
228 *
229 * Used in conjunction with usb_register_dev(). This function is called
230 * when the USB driver is finished with the minor numbers gotten from a
231 * call to usb_register_dev() (usually when the device is disconnected
232 * from the system.)
233 *
234 * This function also removes the usb class device from the sysfs tree.
235 *
236 * This should be called by all drivers that use the USB major number.
237 */
238 void usb_deregister_dev(struct usb_interface *intf,
239 struct usb_class_driver *class_driver)
240 {
241 int minor_base = class_driver->minor_base;
242 char name[20];
243
244 #ifdef CONFIG_USB_DYNAMIC_MINORS
245 minor_base = 0;
246 #endif
247
248 if (intf->minor == -1)
249 return;
250
251 dbg ("removing %d minor", intf->minor);
252
253 down_write(&minor_rwsem);
254 usb_minors[intf->minor] = NULL;
255 up_write(&minor_rwsem);
256
257 snprintf(name, sizeof(name), class_driver->name, intf->minor - minor_base);
258 device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
259 intf->usb_dev = NULL;
260 intf->minor = -1;
261 destroy_usb_class();
262 }
263 EXPORT_SYMBOL_GPL(usb_deregister_dev);
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