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Commit | Line | Data |
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aa1f3bb5 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
f30c2269 | 3 | * drivers/usb/core/file.c |
1da177e4 LT |
4 | * |
5 | * (C) Copyright Linus Torvalds 1999 | |
6 | * (C) Copyright Johannes Erdfelt 1999-2001 | |
7 | * (C) Copyright Andreas Gal 1999 | |
8 | * (C) Copyright Gregory P. Smith 1999 | |
9 | * (C) Copyright Deti Fliegl 1999 (new USB architecture) | |
10 | * (C) Copyright Randy Dunlap 2000 | |
11 | * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id, | |
469271f8 | 12 | * more docs, etc) |
1da177e4 LT |
13 | * (C) Copyright Yggdrasil Computing, Inc. 2000 |
14 | * (usb_device_id matching changes by Adam J. Richter) | |
15 | * (C) Copyright Greg Kroah-Hartman 2002-2003 | |
16 | * | |
b65fba3d | 17 | * Released under the GPLv2 only. |
1da177e4 LT |
18 | */ |
19 | ||
1da177e4 | 20 | #include <linux/module.h> |
1da177e4 | 21 | #include <linux/errno.h> |
d4ead16f | 22 | #include <linux/rwsem.h> |
5a0e3ad6 | 23 | #include <linux/slab.h> |
f8868ed0 | 24 | #include <linux/string.h> |
1da177e4 LT |
25 | #include <linux/usb.h> |
26 | ||
6d5e8254 GKH |
27 | #include "usb.h" |
28 | ||
1da177e4 | 29 | #define MAX_USB_MINORS 256 |
99ac48f5 | 30 | static const struct file_operations *usb_minors[MAX_USB_MINORS]; |
d4ead16f | 31 | static DECLARE_RWSEM(minor_rwsem); |
2f86a96b | 32 | static DEFINE_MUTEX(init_usb_class_mutex); |
1da177e4 | 33 | |
1335f2d2 | 34 | static int usb_open(struct inode *inode, struct file *file) |
1da177e4 | 35 | { |
1da177e4 | 36 | int err = -ENODEV; |
e84f9e57 | 37 | const struct file_operations *new_fops; |
1da177e4 | 38 | |
d4ead16f | 39 | down_read(&minor_rwsem); |
e84f9e57 | 40 | new_fops = fops_get(usb_minors[iminor(inode)]); |
1da177e4 | 41 | |
e84f9e57 | 42 | if (!new_fops) |
d4ead16f | 43 | goto done; |
1da177e4 | 44 | |
e84f9e57 | 45 | replace_fops(file, new_fops); |
1da177e4 LT |
46 | /* Curiouser and curiouser... NULL ->open() as "no device" ? */ |
47 | if (file->f_op->open) | |
469271f8 | 48 | err = file->f_op->open(inode, file); |
d4ead16f AS |
49 | done: |
50 | up_read(&minor_rwsem); | |
1da177e4 LT |
51 | return err; |
52 | } | |
53 | ||
066202dd | 54 | static const struct file_operations usb_fops = { |
1da177e4 LT |
55 | .owner = THIS_MODULE, |
56 | .open = usb_open, | |
6038f373 | 57 | .llseek = noop_llseek, |
1da177e4 LT |
58 | }; |
59 | ||
43104f1d GKH |
60 | static struct usb_class { |
61 | struct kref kref; | |
62 | struct class *class; | |
63 | } *usb_class; | |
1da177e4 | 64 | |
2c9ede55 | 65 | static char *usb_devnode(struct device *dev, umode_t *mode) |
f7a386c5 KS |
66 | { |
67 | struct usb_class_driver *drv; | |
68 | ||
69 | drv = dev_get_drvdata(dev); | |
e454cea2 | 70 | if (!drv || !drv->devnode) |
f7a386c5 | 71 | return NULL; |
e454cea2 | 72 | return drv->devnode(dev, mode); |
f7a386c5 KS |
73 | } |
74 | ||
43104f1d | 75 | static int init_usb_class(void) |
1da177e4 | 76 | { |
43104f1d | 77 | int result = 0; |
1da177e4 | 78 | |
43104f1d GKH |
79 | if (usb_class != NULL) { |
80 | kref_get(&usb_class->kref); | |
81 | goto exit; | |
82 | } | |
83 | ||
84 | usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); | |
85 | if (!usb_class) { | |
86 | result = -ENOMEM; | |
87 | goto exit; | |
1da177e4 LT |
88 | } |
89 | ||
43104f1d | 90 | kref_init(&usb_class->kref); |
7e97243c | 91 | usb_class->class = class_create(THIS_MODULE, "usbmisc"); |
43104f1d | 92 | if (IS_ERR(usb_class->class)) { |
de5535f5 | 93 | result = PTR_ERR(usb_class->class); |
69a85942 | 94 | printk(KERN_ERR "class_create failed for usb devices\n"); |
43104f1d GKH |
95 | kfree(usb_class); |
96 | usb_class = NULL; | |
ed7487c2 | 97 | goto exit; |
1da177e4 | 98 | } |
e454cea2 | 99 | usb_class->class->devnode = usb_devnode; |
1da177e4 | 100 | |
43104f1d GKH |
101 | exit: |
102 | return result; | |
103 | } | |
104 | ||
105 | static void release_usb_class(struct kref *kref) | |
106 | { | |
107 | /* Ok, we cheat as we know we only have one usb_class */ | |
108 | class_destroy(usb_class->class); | |
109 | kfree(usb_class); | |
110 | usb_class = NULL; | |
111 | } | |
112 | ||
113 | static void destroy_usb_class(void) | |
114 | { | |
2f86a96b AK |
115 | mutex_lock(&init_usb_class_mutex); |
116 | kref_put(&usb_class->kref, release_usb_class); | |
117 | mutex_unlock(&init_usb_class_mutex); | |
43104f1d GKH |
118 | } |
119 | ||
120 | int usb_major_init(void) | |
121 | { | |
122 | int error; | |
123 | ||
124 | error = register_chrdev(USB_MAJOR, "usb", &usb_fops); | |
125 | if (error) | |
69a85942 GKH |
126 | printk(KERN_ERR "Unable to get major %d for usb devices\n", |
127 | USB_MAJOR); | |
43104f1d | 128 | |
1da177e4 LT |
129 | return error; |
130 | } | |
131 | ||
132 | void usb_major_cleanup(void) | |
133 | { | |
1da177e4 LT |
134 | unregister_chrdev(USB_MAJOR, "usb"); |
135 | } | |
136 | ||
137 | /** | |
138 | * usb_register_dev - register a USB device, and ask for a minor number | |
139 | * @intf: pointer to the usb_interface that is being registered | |
140 | * @class_driver: pointer to the usb_class_driver for this device | |
141 | * | |
142 | * This should be called by all USB drivers that use the USB major number. | |
143 | * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be | |
144 | * dynamically allocated out of the list of available ones. If it is not | |
145 | * enabled, the minor number will be based on the next available free minor, | |
146 | * starting at the class_driver->minor_base. | |
147 | * | |
d6e5bcf4 | 148 | * This function also creates a usb class device in the sysfs tree. |
1da177e4 LT |
149 | * |
150 | * usb_deregister_dev() must be called when the driver is done with | |
151 | * the minor numbers given out by this function. | |
152 | * | |
626f090c | 153 | * Return: -EINVAL if something bad happens with trying to register a |
1da177e4 LT |
154 | * device, and 0 on success. |
155 | */ | |
156 | int usb_register_dev(struct usb_interface *intf, | |
157 | struct usb_class_driver *class_driver) | |
158 | { | |
0026e005 | 159 | int retval; |
1da177e4 | 160 | int minor_base = class_driver->minor_base; |
0026e005 | 161 | int minor; |
7071a3ce | 162 | char name[20]; |
1da177e4 LT |
163 | |
164 | #ifdef CONFIG_USB_DYNAMIC_MINORS | |
469271f8 | 165 | /* |
1da177e4 LT |
166 | * We don't care what the device tries to start at, we want to start |
167 | * at zero to pack the devices into the smallest available space with | |
168 | * no holes in the minor range. | |
169 | */ | |
170 | minor_base = 0; | |
171 | #endif | |
1da177e4 LT |
172 | |
173 | if (class_driver->fops == NULL) | |
0026e005 AS |
174 | return -EINVAL; |
175 | if (intf->minor >= 0) | |
176 | return -EADDRINUSE; | |
177 | ||
2f86a96b | 178 | mutex_lock(&init_usb_class_mutex); |
0026e005 | 179 | retval = init_usb_class(); |
2f86a96b AK |
180 | mutex_unlock(&init_usb_class_mutex); |
181 | ||
0026e005 AS |
182 | if (retval) |
183 | return retval; | |
184 | ||
079d440e | 185 | dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base); |
1da177e4 | 186 | |
d4ead16f | 187 | down_write(&minor_rwsem); |
1da177e4 LT |
188 | for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { |
189 | if (usb_minors[minor]) | |
190 | continue; | |
191 | ||
192 | usb_minors[minor] = class_driver->fops; | |
0026e005 | 193 | intf->minor = minor; |
1da177e4 LT |
194 | break; |
195 | } | |
d4ead16f | 196 | up_write(&minor_rwsem); |
0026e005 AS |
197 | if (intf->minor < 0) |
198 | return -EXFULL; | |
1da177e4 | 199 | |
1da177e4 | 200 | /* create a usb class device for this usb interface */ |
7071a3ce | 201 | snprintf(name, sizeof(name), class_driver->name, minor - minor_base); |
b0b090e5 | 202 | intf->usb_dev = device_create(usb_class->class, &intf->dev, |
f7a386c5 | 203 | MKDEV(USB_MAJOR, minor), class_driver, |
f8868ed0 | 204 | "%s", kbasename(name)); |
0873c764 | 205 | if (IS_ERR(intf->usb_dev)) { |
d4ead16f | 206 | down_write(&minor_rwsem); |
0026e005 AS |
207 | usb_minors[minor] = NULL; |
208 | intf->minor = -1; | |
d4ead16f | 209 | up_write(&minor_rwsem); |
0873c764 | 210 | retval = PTR_ERR(intf->usb_dev); |
1da177e4 | 211 | } |
1da177e4 LT |
212 | return retval; |
213 | } | |
782e70c6 | 214 | EXPORT_SYMBOL_GPL(usb_register_dev); |
1da177e4 LT |
215 | |
216 | /** | |
217 | * usb_deregister_dev - deregister a USB device's dynamic minor. | |
218 | * @intf: pointer to the usb_interface that is being deregistered | |
219 | * @class_driver: pointer to the usb_class_driver for this device | |
220 | * | |
221 | * Used in conjunction with usb_register_dev(). This function is called | |
222 | * when the USB driver is finished with the minor numbers gotten from a | |
223 | * call to usb_register_dev() (usually when the device is disconnected | |
224 | * from the system.) | |
225 | * | |
d6e5bcf4 GKH |
226 | * This function also removes the usb class device from the sysfs tree. |
227 | * | |
1da177e4 LT |
228 | * This should be called by all drivers that use the USB major number. |
229 | */ | |
230 | void usb_deregister_dev(struct usb_interface *intf, | |
231 | struct usb_class_driver *class_driver) | |
232 | { | |
1da177e4 LT |
233 | if (intf->minor == -1) |
234 | return; | |
235 | ||
079d440e | 236 | dev_dbg(&intf->dev, "removing %d minor\n", intf->minor); |
1da177e4 | 237 | |
d4ead16f | 238 | down_write(&minor_rwsem); |
1da177e4 | 239 | usb_minors[intf->minor] = NULL; |
d4ead16f | 240 | up_write(&minor_rwsem); |
1da177e4 | 241 | |
0873c764 GKH |
242 | device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); |
243 | intf->usb_dev = NULL; | |
1da177e4 | 244 | intf->minor = -1; |
43104f1d | 245 | destroy_usb_class(); |
1da177e4 | 246 | } |
782e70c6 | 247 | EXPORT_SYMBOL_GPL(usb_deregister_dev); |