blob: ea337a718cc1ca38945d3c42e6d0f75d157083b6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * drivers/usb/core/file.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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,
Matthias Beyer469271f2013-10-10 23:41:27 +020011 * more docs, etc)
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 * (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
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/errno.h>
Alan Sternd4ead162007-05-22 11:46:41 -040020#include <linux/rwsem.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/usb.h>
23
Greg KH6d5e8252005-04-18 17:39:24 -070024#include "usb.h"
25
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#define MAX_USB_MINORS 256
Arjan van de Ven99ac48f2006-03-28 01:56:41 -080027static const struct file_operations *usb_minors[MAX_USB_MINORS];
Alan Sternd4ead162007-05-22 11:46:41 -040028static DECLARE_RWSEM(minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Matthias Beyer1335f2d2013-10-10 23:41:28 +020030static int usb_open(struct inode *inode, struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -070031{
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 int err = -ENODEV;
Al Viroe84f9e52013-09-22 14:17:15 -040033 const struct file_operations *new_fops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Alan Sternd4ead162007-05-22 11:46:41 -040035 down_read(&minor_rwsem);
Al Viroe84f9e52013-09-22 14:17:15 -040036 new_fops = fops_get(usb_minors[iminor(inode)]);
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
Al Viroe84f9e52013-09-22 14:17:15 -040038 if (!new_fops)
Alan Sternd4ead162007-05-22 11:46:41 -040039 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Al Viroe84f9e52013-09-22 14:17:15 -040041 replace_fops(file, new_fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 /* Curiouser and curiouser... NULL ->open() as "no device" ? */
43 if (file->f_op->open)
Matthias Beyer469271f2013-10-10 23:41:27 +020044 err = file->f_op->open(inode, file);
Alan Sternd4ead162007-05-22 11:46:41 -040045 done:
46 up_read(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 return err;
48}
49
Luiz Fernando N. Capitulino066202d2006-08-05 20:37:11 -030050static const struct file_operations usb_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 .owner = THIS_MODULE,
52 .open = usb_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +020053 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070054};
55
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070056static struct usb_class {
57 struct kref kref;
58 struct class *class;
59} *usb_class;
60
Al Viro2c9ede52011-07-23 20:24:48 -040061static char *usb_devnode(struct device *dev, umode_t *mode)
Kay Sieversf7a386c2009-04-30 15:23:42 +020062{
63 struct usb_class_driver *drv;
64
65 drv = dev_get_drvdata(dev);
Kay Sieverse454cea2009-09-18 23:01:12 +020066 if (!drv || !drv->devnode)
Kay Sieversf7a386c2009-04-30 15:23:42 +020067 return NULL;
Kay Sieverse454cea2009-09-18 23:01:12 +020068 return drv->devnode(dev, mode);
Kay Sieversf7a386c2009-04-30 15:23:42 +020069}
70
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070071static int init_usb_class(void)
72{
73 int result = 0;
74
75 if (usb_class != NULL) {
76 kref_get(&usb_class->kref);
77 goto exit;
78 }
79
80 usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
81 if (!usb_class) {
82 result = -ENOMEM;
83 goto exit;
84 }
85
86 kref_init(&usb_class->kref);
Greg Kroah-Hartman7e972432012-04-25 17:22:37 -070087 usb_class->class = class_create(THIS_MODULE, "usbmisc");
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070088 if (IS_ERR(usb_class->class)) {
Alexey Khoroshilovde5535f2013-06-06 01:27:15 +040089 result = PTR_ERR(usb_class->class);
Greg Kroah-Hartman69a85942008-08-14 09:37:34 -070090 printk(KERN_ERR "class_create failed for usb devices\n");
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070091 kfree(usb_class);
92 usb_class = NULL;
Dan Carpentered7487c2009-11-10 11:02:08 +020093 goto exit;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070094 }
Kay Sieverse454cea2009-09-18 23:01:12 +020095 usb_class->class->devnode = usb_devnode;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -070096
97exit:
98 return result;
99}
100
101static void release_usb_class(struct kref *kref)
102{
103 /* Ok, we cheat as we know we only have one usb_class */
104 class_destroy(usb_class->class);
105 kfree(usb_class);
106 usb_class = NULL;
107}
108
109static void destroy_usb_class(void)
110{
111 if (usb_class)
112 kref_put(&usb_class->kref, release_usb_class);
113}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
115int usb_major_init(void)
116{
117 int error;
118
119 error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700120 if (error)
Greg Kroah-Hartman69a85942008-08-14 09:37:34 -0700121 printk(KERN_ERR "Unable to get major %d for usb devices\n",
122 USB_MAJOR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 return error;
125}
126
127void usb_major_cleanup(void)
128{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 unregister_chrdev(USB_MAJOR, "usb");
130}
131
132/**
133 * usb_register_dev - register a USB device, and ask for a minor number
134 * @intf: pointer to the usb_interface that is being registered
135 * @class_driver: pointer to the usb_class_driver for this device
136 *
137 * This should be called by all USB drivers that use the USB major number.
138 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
139 * dynamically allocated out of the list of available ones. If it is not
140 * enabled, the minor number will be based on the next available free minor,
141 * starting at the class_driver->minor_base.
142 *
Greg Kroah-Hartmand6e5bcf2005-06-20 21:15:16 -0700143 * This function also creates a usb class device in the sysfs tree.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 *
145 * usb_deregister_dev() must be called when the driver is done with
146 * the minor numbers given out by this function.
147 *
Yacine Belkadi626f0902013-08-02 20:10:04 +0200148 * Return: -EINVAL if something bad happens with trying to register a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 * device, and 0 on success.
150 */
151int usb_register_dev(struct usb_interface *intf,
152 struct usb_class_driver *class_driver)
153{
Alan Stern0026e002010-09-21 15:01:53 -0400154 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 int minor_base = class_driver->minor_base;
Alan Stern0026e002010-09-21 15:01:53 -0400156 int minor;
Kay Sievers7071a3c2008-05-02 06:02:41 +0200157 char name[20];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 char *temp;
159
160#ifdef CONFIG_USB_DYNAMIC_MINORS
Matthias Beyer469271f2013-10-10 23:41:27 +0200161 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 * We don't care what the device tries to start at, we want to start
163 * at zero to pack the devices into the smallest available space with
164 * no holes in the minor range.
165 */
166 minor_base = 0;
167#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
169 if (class_driver->fops == NULL)
Alan Stern0026e002010-09-21 15:01:53 -0400170 return -EINVAL;
171 if (intf->minor >= 0)
172 return -EADDRINUSE;
173
174 retval = init_usb_class();
175 if (retval)
176 return retval;
177
Greg Kroah-Hartman079d4402012-05-01 21:33:35 -0700178 dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
Alan Sternd4ead162007-05-22 11:46:41 -0400180 down_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
182 if (usb_minors[minor])
183 continue;
184
185 usb_minors[minor] = class_driver->fops;
Alan Stern0026e002010-09-21 15:01:53 -0400186 intf->minor = minor;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 break;
188 }
Alan Sternd4ead162007-05-22 11:46:41 -0400189 up_write(&minor_rwsem);
Alan Stern0026e002010-09-21 15:01:53 -0400190 if (intf->minor < 0)
191 return -EXFULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 /* create a usb class device for this usb interface */
Kay Sievers7071a3c2008-05-02 06:02:41 +0200194 snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 temp = strrchr(name, '/');
Kay Sievers7071a3c2008-05-02 06:02:41 +0200196 if (temp && (temp[1] != '\0'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 ++temp;
198 else
199 temp = name;
Greg Kroah-Hartmanb0b090e2008-07-21 20:03:34 -0700200 intf->usb_dev = device_create(usb_class->class, &intf->dev,
Kay Sieversf7a386c2009-04-30 15:23:42 +0200201 MKDEV(USB_MAJOR, minor), class_driver,
Greg Kroah-Hartmanb0b090e2008-07-21 20:03:34 -0700202 "%s", temp);
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700203 if (IS_ERR(intf->usb_dev)) {
Alan Sternd4ead162007-05-22 11:46:41 -0400204 down_write(&minor_rwsem);
Alan Stern0026e002010-09-21 15:01:53 -0400205 usb_minors[minor] = NULL;
206 intf->minor = -1;
Alan Sternd4ead162007-05-22 11:46:41 -0400207 up_write(&minor_rwsem);
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700208 retval = PTR_ERR(intf->usb_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 return retval;
211}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600212EXPORT_SYMBOL_GPL(usb_register_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
214/**
215 * usb_deregister_dev - deregister a USB device's dynamic minor.
216 * @intf: pointer to the usb_interface that is being deregistered
217 * @class_driver: pointer to the usb_class_driver for this device
218 *
219 * Used in conjunction with usb_register_dev(). This function is called
220 * when the USB driver is finished with the minor numbers gotten from a
221 * call to usb_register_dev() (usually when the device is disconnected
222 * from the system.)
223 *
Greg Kroah-Hartmand6e5bcf2005-06-20 21:15:16 -0700224 * This function also removes the usb class device from the sysfs tree.
225 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 * This should be called by all drivers that use the USB major number.
227 */
228void usb_deregister_dev(struct usb_interface *intf,
229 struct usb_class_driver *class_driver)
230{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 if (intf->minor == -1)
232 return;
233
Greg Kroah-Hartman079d4402012-05-01 21:33:35 -0700234 dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Alan Sternd4ead162007-05-22 11:46:41 -0400236 down_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 usb_minors[intf->minor] = NULL;
Alan Sternd4ead162007-05-22 11:46:41 -0400238 up_write(&minor_rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
Greg Kroah-Hartman0873c762006-06-20 13:09:50 -0700240 device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
241 intf->usb_dev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 intf->minor = -1;
Greg Kroah-Hartman43104f12006-06-20 15:14:07 -0700243 destroy_usb_class();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600245EXPORT_SYMBOL_GPL(usb_deregister_dev);