Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Uwe Zeisberger | f30c226 | 2006-10-03 23:01:26 +0200 | [diff] [blame] | 2 | * drivers/usb/core/file.c |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/spinlock.h> |
| 20 | #include <linux/errno.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | #include <linux/usb.h> |
| 22 | |
Greg KH | 6d5e825 | 2005-04-18 17:39:24 -0700 | [diff] [blame] | 23 | #include "usb.h" |
| 24 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #define MAX_USB_MINORS 256 |
Arjan van de Ven | 99ac48f | 2006-03-28 01:56:41 -0800 | [diff] [blame] | 26 | static const struct file_operations *usb_minors[MAX_USB_MINORS]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | static DEFINE_SPINLOCK(minor_lock); |
| 28 | |
| 29 | static int usb_open(struct inode * inode, struct file * file) |
| 30 | { |
| 31 | int minor = iminor(inode); |
Arjan van de Ven | 99ac48f | 2006-03-28 01:56:41 -0800 | [diff] [blame] | 32 | const struct file_operations *c; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | int err = -ENODEV; |
Arjan van de Ven | 99ac48f | 2006-03-28 01:56:41 -0800 | [diff] [blame] | 34 | const struct file_operations *old_fops, *new_fops = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
| 36 | spin_lock (&minor_lock); |
| 37 | c = usb_minors[minor]; |
| 38 | |
| 39 | if (!c || !(new_fops = fops_get(c))) { |
| 40 | spin_unlock(&minor_lock); |
| 41 | return err; |
| 42 | } |
| 43 | spin_unlock(&minor_lock); |
| 44 | |
| 45 | old_fops = file->f_op; |
| 46 | file->f_op = new_fops; |
| 47 | /* Curiouser and curiouser... NULL ->open() as "no device" ? */ |
| 48 | if (file->f_op->open) |
| 49 | err = file->f_op->open(inode,file); |
| 50 | if (err) { |
| 51 | fops_put(file->f_op); |
| 52 | file->f_op = fops_get(old_fops); |
| 53 | } |
| 54 | fops_put(old_fops); |
| 55 | return err; |
| 56 | } |
| 57 | |
Luiz Fernando N. Capitulino | 066202d | 2006-08-05 20:37:11 -0300 | [diff] [blame] | 58 | static const struct file_operations usb_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | .owner = THIS_MODULE, |
| 60 | .open = usb_open, |
| 61 | }; |
| 62 | |
Greg Kroah-Hartman | 43104f1 | 2006-06-20 15:14:07 -0700 | [diff] [blame] | 63 | static struct usb_class { |
| 64 | struct kref kref; |
| 65 | struct class *class; |
| 66 | } *usb_class; |
| 67 | |
| 68 | static int init_usb_class(void) |
| 69 | { |
| 70 | int result = 0; |
| 71 | |
| 72 | if (usb_class != NULL) { |
| 73 | kref_get(&usb_class->kref); |
| 74 | goto exit; |
| 75 | } |
| 76 | |
| 77 | usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); |
| 78 | if (!usb_class) { |
| 79 | result = -ENOMEM; |
| 80 | goto exit; |
| 81 | } |
| 82 | |
| 83 | kref_init(&usb_class->kref); |
| 84 | usb_class->class = class_create(THIS_MODULE, "usb"); |
| 85 | if (IS_ERR(usb_class->class)) { |
| 86 | result = IS_ERR(usb_class->class); |
| 87 | err("class_create failed for usb devices"); |
| 88 | kfree(usb_class); |
| 89 | usb_class = NULL; |
| 90 | } |
| 91 | |
| 92 | exit: |
| 93 | return result; |
| 94 | } |
| 95 | |
| 96 | static void release_usb_class(struct kref *kref) |
| 97 | { |
| 98 | /* Ok, we cheat as we know we only have one usb_class */ |
| 99 | class_destroy(usb_class->class); |
| 100 | kfree(usb_class); |
| 101 | usb_class = NULL; |
| 102 | } |
| 103 | |
| 104 | static void destroy_usb_class(void) |
| 105 | { |
| 106 | if (usb_class) |
| 107 | kref_put(&usb_class->kref, release_usb_class); |
| 108 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | |
| 110 | int usb_major_init(void) |
| 111 | { |
| 112 | int error; |
| 113 | |
| 114 | error = register_chrdev(USB_MAJOR, "usb", &usb_fops); |
Greg Kroah-Hartman | 43104f1 | 2006-06-20 15:14:07 -0700 | [diff] [blame] | 115 | if (error) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | err("unable to get major %d for usb devices", USB_MAJOR); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | return error; |
| 119 | } |
| 120 | |
| 121 | void usb_major_cleanup(void) |
| 122 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | unregister_chrdev(USB_MAJOR, "usb"); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * usb_register_dev - register a USB device, and ask for a minor number |
| 128 | * @intf: pointer to the usb_interface that is being registered |
| 129 | * @class_driver: pointer to the usb_class_driver for this device |
| 130 | * |
| 131 | * This should be called by all USB drivers that use the USB major number. |
| 132 | * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be |
| 133 | * dynamically allocated out of the list of available ones. If it is not |
| 134 | * enabled, the minor number will be based on the next available free minor, |
| 135 | * starting at the class_driver->minor_base. |
| 136 | * |
Greg Kroah-Hartman | d6e5bcf | 2005-06-20 21:15:16 -0700 | [diff] [blame] | 137 | * This function also creates a usb class device in the sysfs tree. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | * |
| 139 | * usb_deregister_dev() must be called when the driver is done with |
| 140 | * the minor numbers given out by this function. |
| 141 | * |
| 142 | * Returns -EINVAL if something bad happens with trying to register a |
| 143 | * device, and 0 on success. |
| 144 | */ |
| 145 | int usb_register_dev(struct usb_interface *intf, |
| 146 | struct usb_class_driver *class_driver) |
| 147 | { |
| 148 | int retval = -EINVAL; |
| 149 | int minor_base = class_driver->minor_base; |
| 150 | int minor = 0; |
| 151 | char name[BUS_ID_SIZE]; |
| 152 | char *temp; |
| 153 | |
| 154 | #ifdef CONFIG_USB_DYNAMIC_MINORS |
| 155 | /* |
| 156 | * We don't care what the device tries to start at, we want to start |
| 157 | * at zero to pack the devices into the smallest available space with |
| 158 | * no holes in the minor range. |
| 159 | */ |
| 160 | minor_base = 0; |
| 161 | #endif |
| 162 | intf->minor = -1; |
| 163 | |
| 164 | dbg ("looking for a minor, starting at %d", minor_base); |
| 165 | |
| 166 | if (class_driver->fops == NULL) |
| 167 | goto exit; |
| 168 | |
| 169 | spin_lock (&minor_lock); |
| 170 | for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { |
| 171 | if (usb_minors[minor]) |
| 172 | continue; |
| 173 | |
| 174 | usb_minors[minor] = class_driver->fops; |
| 175 | |
| 176 | retval = 0; |
| 177 | break; |
| 178 | } |
| 179 | spin_unlock (&minor_lock); |
| 180 | |
| 181 | if (retval) |
| 182 | goto exit; |
| 183 | |
Greg Kroah-Hartman | 43104f1 | 2006-06-20 15:14:07 -0700 | [diff] [blame] | 184 | retval = init_usb_class(); |
| 185 | if (retval) |
| 186 | goto exit; |
| 187 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | intf->minor = minor; |
| 189 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | /* create a usb class device for this usb interface */ |
Greg Kroah-Hartman | d6e5bcf | 2005-06-20 21:15:16 -0700 | [diff] [blame] | 191 | snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | temp = strrchr(name, '/'); |
| 193 | if (temp && (temp[1] != 0x00)) |
| 194 | ++temp; |
| 195 | else |
| 196 | temp = name; |
Greg Kroah-Hartman | 0873c76 | 2006-06-20 13:09:50 -0700 | [diff] [blame^] | 197 | intf->usb_dev = device_create(usb_class->class, &intf->dev, |
| 198 | MKDEV(USB_MAJOR, minor), "%s", temp); |
| 199 | if (IS_ERR(intf->usb_dev)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | spin_lock (&minor_lock); |
| 201 | usb_minors[intf->minor] = NULL; |
| 202 | spin_unlock (&minor_lock); |
Greg Kroah-Hartman | 0873c76 | 2006-06-20 13:09:50 -0700 | [diff] [blame^] | 203 | retval = PTR_ERR(intf->usb_dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | } |
| 205 | exit: |
| 206 | return retval; |
| 207 | } |
| 208 | EXPORT_SYMBOL(usb_register_dev); |
| 209 | |
| 210 | /** |
| 211 | * usb_deregister_dev - deregister a USB device's dynamic minor. |
| 212 | * @intf: pointer to the usb_interface that is being deregistered |
| 213 | * @class_driver: pointer to the usb_class_driver for this device |
| 214 | * |
| 215 | * Used in conjunction with usb_register_dev(). This function is called |
| 216 | * when the USB driver is finished with the minor numbers gotten from a |
| 217 | * call to usb_register_dev() (usually when the device is disconnected |
| 218 | * from the system.) |
| 219 | * |
Greg Kroah-Hartman | d6e5bcf | 2005-06-20 21:15:16 -0700 | [diff] [blame] | 220 | * This function also removes the usb class device from the sysfs tree. |
| 221 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | * This should be called by all drivers that use the USB major number. |
| 223 | */ |
| 224 | void usb_deregister_dev(struct usb_interface *intf, |
| 225 | struct usb_class_driver *class_driver) |
| 226 | { |
| 227 | int minor_base = class_driver->minor_base; |
| 228 | char name[BUS_ID_SIZE]; |
| 229 | |
| 230 | #ifdef CONFIG_USB_DYNAMIC_MINORS |
| 231 | minor_base = 0; |
| 232 | #endif |
| 233 | |
| 234 | if (intf->minor == -1) |
| 235 | return; |
| 236 | |
| 237 | dbg ("removing %d minor", intf->minor); |
| 238 | |
| 239 | spin_lock (&minor_lock); |
| 240 | usb_minors[intf->minor] = NULL; |
| 241 | spin_unlock (&minor_lock); |
| 242 | |
| 243 | snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); |
Greg Kroah-Hartman | 0873c76 | 2006-06-20 13:09:50 -0700 | [diff] [blame^] | 244 | device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); |
| 245 | intf->usb_dev = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | intf->minor = -1; |
Greg Kroah-Hartman | 43104f1 | 2006-06-20 15:14:07 -0700 | [diff] [blame] | 247 | destroy_usb_class(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | } |
| 249 | EXPORT_SYMBOL(usb_deregister_dev); |
| 250 | |
| 251 | |