11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * drivers/usb/file.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * (C) Copyright Linus Torvalds 1999 51da177e4SLinus Torvalds * (C) Copyright Johannes Erdfelt 1999-2001 61da177e4SLinus Torvalds * (C) Copyright Andreas Gal 1999 71da177e4SLinus Torvalds * (C) Copyright Gregory P. Smith 1999 81da177e4SLinus Torvalds * (C) Copyright Deti Fliegl 1999 (new USB architecture) 91da177e4SLinus Torvalds * (C) Copyright Randy Dunlap 2000 101da177e4SLinus Torvalds * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id, 111da177e4SLinus Torvalds more docs, etc) 121da177e4SLinus Torvalds * (C) Copyright Yggdrasil Computing, Inc. 2000 131da177e4SLinus Torvalds * (usb_device_id matching changes by Adam J. Richter) 141da177e4SLinus Torvalds * (C) Copyright Greg Kroah-Hartman 2002-2003 151da177e4SLinus Torvalds * 161da177e4SLinus Torvalds */ 171da177e4SLinus Torvalds 181da177e4SLinus Torvalds #include <linux/config.h> 191da177e4SLinus Torvalds #include <linux/module.h> 201da177e4SLinus Torvalds #include <linux/spinlock.h> 211da177e4SLinus Torvalds #include <linux/errno.h> 221da177e4SLinus Torvalds #include <linux/usb.h> 231da177e4SLinus Torvalds 246d5e8254SGreg KH #include "usb.h" 256d5e8254SGreg KH 261da177e4SLinus Torvalds #define MAX_USB_MINORS 256 2799ac48f5SArjan van de Ven static const struct file_operations *usb_minors[MAX_USB_MINORS]; 281da177e4SLinus Torvalds static DEFINE_SPINLOCK(minor_lock); 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds static int usb_open(struct inode * inode, struct file * file) 311da177e4SLinus Torvalds { 321da177e4SLinus Torvalds int minor = iminor(inode); 3399ac48f5SArjan van de Ven const struct file_operations *c; 341da177e4SLinus Torvalds int err = -ENODEV; 3599ac48f5SArjan van de Ven const struct file_operations *old_fops, *new_fops = NULL; 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds spin_lock (&minor_lock); 381da177e4SLinus Torvalds c = usb_minors[minor]; 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds if (!c || !(new_fops = fops_get(c))) { 411da177e4SLinus Torvalds spin_unlock(&minor_lock); 421da177e4SLinus Torvalds return err; 431da177e4SLinus Torvalds } 441da177e4SLinus Torvalds spin_unlock(&minor_lock); 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds old_fops = file->f_op; 471da177e4SLinus Torvalds file->f_op = new_fops; 481da177e4SLinus Torvalds /* Curiouser and curiouser... NULL ->open() as "no device" ? */ 491da177e4SLinus Torvalds if (file->f_op->open) 501da177e4SLinus Torvalds err = file->f_op->open(inode,file); 511da177e4SLinus Torvalds if (err) { 521da177e4SLinus Torvalds fops_put(file->f_op); 531da177e4SLinus Torvalds file->f_op = fops_get(old_fops); 541da177e4SLinus Torvalds } 551da177e4SLinus Torvalds fops_put(old_fops); 561da177e4SLinus Torvalds return err; 571da177e4SLinus Torvalds } 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds static struct file_operations usb_fops = { 601da177e4SLinus Torvalds .owner = THIS_MODULE, 611da177e4SLinus Torvalds .open = usb_open, 621da177e4SLinus Torvalds }; 631da177e4SLinus Torvalds 64*43104f1dSGreg Kroah-Hartman static struct usb_class { 65*43104f1dSGreg Kroah-Hartman struct kref kref; 66*43104f1dSGreg Kroah-Hartman struct class *class; 67*43104f1dSGreg Kroah-Hartman } *usb_class; 68*43104f1dSGreg Kroah-Hartman 69*43104f1dSGreg Kroah-Hartman static int init_usb_class(void) 70*43104f1dSGreg Kroah-Hartman { 71*43104f1dSGreg Kroah-Hartman int result = 0; 72*43104f1dSGreg Kroah-Hartman 73*43104f1dSGreg Kroah-Hartman if (usb_class != NULL) { 74*43104f1dSGreg Kroah-Hartman kref_get(&usb_class->kref); 75*43104f1dSGreg Kroah-Hartman goto exit; 76*43104f1dSGreg Kroah-Hartman } 77*43104f1dSGreg Kroah-Hartman 78*43104f1dSGreg Kroah-Hartman usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); 79*43104f1dSGreg Kroah-Hartman if (!usb_class) { 80*43104f1dSGreg Kroah-Hartman result = -ENOMEM; 81*43104f1dSGreg Kroah-Hartman goto exit; 82*43104f1dSGreg Kroah-Hartman } 83*43104f1dSGreg Kroah-Hartman 84*43104f1dSGreg Kroah-Hartman kref_init(&usb_class->kref); 85*43104f1dSGreg Kroah-Hartman usb_class->class = class_create(THIS_MODULE, "usb"); 86*43104f1dSGreg Kroah-Hartman if (IS_ERR(usb_class->class)) { 87*43104f1dSGreg Kroah-Hartman result = IS_ERR(usb_class->class); 88*43104f1dSGreg Kroah-Hartman err("class_create failed for usb devices"); 89*43104f1dSGreg Kroah-Hartman kfree(usb_class); 90*43104f1dSGreg Kroah-Hartman usb_class = NULL; 91*43104f1dSGreg Kroah-Hartman } 92*43104f1dSGreg Kroah-Hartman 93*43104f1dSGreg Kroah-Hartman exit: 94*43104f1dSGreg Kroah-Hartman return result; 95*43104f1dSGreg Kroah-Hartman } 96*43104f1dSGreg Kroah-Hartman 97*43104f1dSGreg Kroah-Hartman static void release_usb_class(struct kref *kref) 98*43104f1dSGreg Kroah-Hartman { 99*43104f1dSGreg Kroah-Hartman /* Ok, we cheat as we know we only have one usb_class */ 100*43104f1dSGreg Kroah-Hartman class_destroy(usb_class->class); 101*43104f1dSGreg Kroah-Hartman kfree(usb_class); 102*43104f1dSGreg Kroah-Hartman usb_class = NULL; 103*43104f1dSGreg Kroah-Hartman } 104*43104f1dSGreg Kroah-Hartman 105*43104f1dSGreg Kroah-Hartman static void destroy_usb_class(void) 106*43104f1dSGreg Kroah-Hartman { 107*43104f1dSGreg Kroah-Hartman if (usb_class) 108*43104f1dSGreg Kroah-Hartman kref_put(&usb_class->kref, release_usb_class); 109*43104f1dSGreg Kroah-Hartman } 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds int usb_major_init(void) 1121da177e4SLinus Torvalds { 1131da177e4SLinus Torvalds int error; 1141da177e4SLinus Torvalds 1151da177e4SLinus Torvalds error = register_chrdev(USB_MAJOR, "usb", &usb_fops); 116*43104f1dSGreg Kroah-Hartman if (error) 1171da177e4SLinus Torvalds err("unable to get major %d for usb devices", USB_MAJOR); 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds return error; 1201da177e4SLinus Torvalds } 1211da177e4SLinus Torvalds 1221da177e4SLinus Torvalds void usb_major_cleanup(void) 1231da177e4SLinus Torvalds { 1241da177e4SLinus Torvalds unregister_chrdev(USB_MAJOR, "usb"); 1251da177e4SLinus Torvalds } 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds /** 1281da177e4SLinus Torvalds * usb_register_dev - register a USB device, and ask for a minor number 1291da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being registered 1301da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 1311da177e4SLinus Torvalds * 1321da177e4SLinus Torvalds * This should be called by all USB drivers that use the USB major number. 1331da177e4SLinus Torvalds * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be 1341da177e4SLinus Torvalds * dynamically allocated out of the list of available ones. If it is not 1351da177e4SLinus Torvalds * enabled, the minor number will be based on the next available free minor, 1361da177e4SLinus Torvalds * starting at the class_driver->minor_base. 1371da177e4SLinus Torvalds * 138d6e5bcf4SGreg Kroah-Hartman * This function also creates a usb class device in the sysfs tree. 1391da177e4SLinus Torvalds * 1401da177e4SLinus Torvalds * usb_deregister_dev() must be called when the driver is done with 1411da177e4SLinus Torvalds * the minor numbers given out by this function. 1421da177e4SLinus Torvalds * 1431da177e4SLinus Torvalds * Returns -EINVAL if something bad happens with trying to register a 1441da177e4SLinus Torvalds * device, and 0 on success. 1451da177e4SLinus Torvalds */ 1461da177e4SLinus Torvalds int usb_register_dev(struct usb_interface *intf, 1471da177e4SLinus Torvalds struct usb_class_driver *class_driver) 1481da177e4SLinus Torvalds { 1491da177e4SLinus Torvalds int retval = -EINVAL; 1501da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 1511da177e4SLinus Torvalds int minor = 0; 1521da177e4SLinus Torvalds char name[BUS_ID_SIZE]; 1531da177e4SLinus Torvalds char *temp; 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 1561da177e4SLinus Torvalds /* 1571da177e4SLinus Torvalds * We don't care what the device tries to start at, we want to start 1581da177e4SLinus Torvalds * at zero to pack the devices into the smallest available space with 1591da177e4SLinus Torvalds * no holes in the minor range. 1601da177e4SLinus Torvalds */ 1611da177e4SLinus Torvalds minor_base = 0; 1621da177e4SLinus Torvalds #endif 1631da177e4SLinus Torvalds intf->minor = -1; 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds dbg ("looking for a minor, starting at %d", minor_base); 1661da177e4SLinus Torvalds 1671da177e4SLinus Torvalds if (class_driver->fops == NULL) 1681da177e4SLinus Torvalds goto exit; 1691da177e4SLinus Torvalds 1701da177e4SLinus Torvalds spin_lock (&minor_lock); 1711da177e4SLinus Torvalds for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { 1721da177e4SLinus Torvalds if (usb_minors[minor]) 1731da177e4SLinus Torvalds continue; 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds usb_minors[minor] = class_driver->fops; 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds retval = 0; 1781da177e4SLinus Torvalds break; 1791da177e4SLinus Torvalds } 1801da177e4SLinus Torvalds spin_unlock (&minor_lock); 1811da177e4SLinus Torvalds 1821da177e4SLinus Torvalds if (retval) 1831da177e4SLinus Torvalds goto exit; 1841da177e4SLinus Torvalds 185*43104f1dSGreg Kroah-Hartman retval = init_usb_class(); 186*43104f1dSGreg Kroah-Hartman if (retval) 187*43104f1dSGreg Kroah-Hartman goto exit; 188*43104f1dSGreg Kroah-Hartman 1891da177e4SLinus Torvalds intf->minor = minor; 1901da177e4SLinus Torvalds 1911da177e4SLinus Torvalds /* create a usb class device for this usb interface */ 192d6e5bcf4SGreg Kroah-Hartman snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base); 1931da177e4SLinus Torvalds temp = strrchr(name, '/'); 1941da177e4SLinus Torvalds if (temp && (temp[1] != 0x00)) 1951da177e4SLinus Torvalds ++temp; 1961da177e4SLinus Torvalds else 1971da177e4SLinus Torvalds temp = name; 198*43104f1dSGreg Kroah-Hartman intf->usb_dev = device_create(usb_class->class, &intf->dev, 199bd009496SGreg Kroah-Hartman MKDEV(USB_MAJOR, minor), "%s", temp); 200bd009496SGreg Kroah-Hartman if (IS_ERR(intf->usb_dev)) { 2011da177e4SLinus Torvalds spin_lock (&minor_lock); 2021da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 2031da177e4SLinus Torvalds spin_unlock (&minor_lock); 204bd009496SGreg Kroah-Hartman retval = PTR_ERR(intf->usb_dev); 2051da177e4SLinus Torvalds } 2061da177e4SLinus Torvalds exit: 2071da177e4SLinus Torvalds return retval; 2081da177e4SLinus Torvalds } 2091da177e4SLinus Torvalds EXPORT_SYMBOL(usb_register_dev); 2101da177e4SLinus Torvalds 2111da177e4SLinus Torvalds /** 2121da177e4SLinus Torvalds * usb_deregister_dev - deregister a USB device's dynamic minor. 2131da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being deregistered 2141da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 2151da177e4SLinus Torvalds * 2161da177e4SLinus Torvalds * Used in conjunction with usb_register_dev(). This function is called 2171da177e4SLinus Torvalds * when the USB driver is finished with the minor numbers gotten from a 2181da177e4SLinus Torvalds * call to usb_register_dev() (usually when the device is disconnected 2191da177e4SLinus Torvalds * from the system.) 2201da177e4SLinus Torvalds * 221d6e5bcf4SGreg Kroah-Hartman * This function also removes the usb class device from the sysfs tree. 2221da177e4SLinus Torvalds * 2231da177e4SLinus Torvalds * This should be called by all drivers that use the USB major number. 2241da177e4SLinus Torvalds */ 2251da177e4SLinus Torvalds void usb_deregister_dev(struct usb_interface *intf, 2261da177e4SLinus Torvalds struct usb_class_driver *class_driver) 2271da177e4SLinus Torvalds { 2281da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 2291da177e4SLinus Torvalds char name[BUS_ID_SIZE]; 2301da177e4SLinus Torvalds 2311da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 2321da177e4SLinus Torvalds minor_base = 0; 2331da177e4SLinus Torvalds #endif 2341da177e4SLinus Torvalds 2351da177e4SLinus Torvalds if (intf->minor == -1) 2361da177e4SLinus Torvalds return; 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds dbg ("removing %d minor", intf->minor); 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds spin_lock (&minor_lock); 2411da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 2421da177e4SLinus Torvalds spin_unlock (&minor_lock); 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); 245*43104f1dSGreg Kroah-Hartman device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); 246bd009496SGreg Kroah-Hartman intf->usb_dev = NULL; 2471da177e4SLinus Torvalds intf->minor = -1; 248*43104f1dSGreg Kroah-Hartman destroy_usb_class(); 2491da177e4SLinus Torvalds } 2501da177e4SLinus Torvalds EXPORT_SYMBOL(usb_deregister_dev); 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds 253