11da177e4SLinus Torvalds /* 2f30c2269SUwe Zeisberger * drivers/usb/core/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/module.h> 191da177e4SLinus Torvalds #include <linux/errno.h> 20*d4ead16fSAlan Stern #include <linux/rwsem.h> 211da177e4SLinus Torvalds #include <linux/usb.h> 221da177e4SLinus Torvalds 236d5e8254SGreg KH #include "usb.h" 246d5e8254SGreg KH 251da177e4SLinus Torvalds #define MAX_USB_MINORS 256 2699ac48f5SArjan van de Ven static const struct file_operations *usb_minors[MAX_USB_MINORS]; 27*d4ead16fSAlan Stern static DECLARE_RWSEM(minor_rwsem); 281da177e4SLinus Torvalds 291da177e4SLinus Torvalds static int usb_open(struct inode * inode, struct file * file) 301da177e4SLinus Torvalds { 311da177e4SLinus Torvalds int minor = iminor(inode); 3299ac48f5SArjan van de Ven const struct file_operations *c; 331da177e4SLinus Torvalds int err = -ENODEV; 3499ac48f5SArjan van de Ven const struct file_operations *old_fops, *new_fops = NULL; 351da177e4SLinus Torvalds 36*d4ead16fSAlan Stern down_read(&minor_rwsem); 371da177e4SLinus Torvalds c = usb_minors[minor]; 381da177e4SLinus Torvalds 39*d4ead16fSAlan Stern if (!c || !(new_fops = fops_get(c))) 40*d4ead16fSAlan Stern goto done; 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds old_fops = file->f_op; 431da177e4SLinus Torvalds file->f_op = new_fops; 441da177e4SLinus Torvalds /* Curiouser and curiouser... NULL ->open() as "no device" ? */ 451da177e4SLinus Torvalds if (file->f_op->open) 461da177e4SLinus Torvalds err = file->f_op->open(inode,file); 471da177e4SLinus Torvalds if (err) { 481da177e4SLinus Torvalds fops_put(file->f_op); 491da177e4SLinus Torvalds file->f_op = fops_get(old_fops); 501da177e4SLinus Torvalds } 511da177e4SLinus Torvalds fops_put(old_fops); 52*d4ead16fSAlan Stern done: 53*d4ead16fSAlan Stern up_read(&minor_rwsem); 541da177e4SLinus Torvalds return err; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 57066202ddSLuiz Fernando N. Capitulino static const struct file_operations usb_fops = { 581da177e4SLinus Torvalds .owner = THIS_MODULE, 591da177e4SLinus Torvalds .open = usb_open, 601da177e4SLinus Torvalds }; 611da177e4SLinus Torvalds 6243104f1dSGreg Kroah-Hartman static struct usb_class { 6343104f1dSGreg Kroah-Hartman struct kref kref; 6443104f1dSGreg Kroah-Hartman struct class *class; 6543104f1dSGreg Kroah-Hartman } *usb_class; 6643104f1dSGreg Kroah-Hartman 6743104f1dSGreg Kroah-Hartman static int init_usb_class(void) 6843104f1dSGreg Kroah-Hartman { 6943104f1dSGreg Kroah-Hartman int result = 0; 7043104f1dSGreg Kroah-Hartman 7143104f1dSGreg Kroah-Hartman if (usb_class != NULL) { 7243104f1dSGreg Kroah-Hartman kref_get(&usb_class->kref); 7343104f1dSGreg Kroah-Hartman goto exit; 7443104f1dSGreg Kroah-Hartman } 7543104f1dSGreg Kroah-Hartman 7643104f1dSGreg Kroah-Hartman usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); 7743104f1dSGreg Kroah-Hartman if (!usb_class) { 7843104f1dSGreg Kroah-Hartman result = -ENOMEM; 7943104f1dSGreg Kroah-Hartman goto exit; 8043104f1dSGreg Kroah-Hartman } 8143104f1dSGreg Kroah-Hartman 8243104f1dSGreg Kroah-Hartman kref_init(&usb_class->kref); 8343104f1dSGreg Kroah-Hartman usb_class->class = class_create(THIS_MODULE, "usb"); 8443104f1dSGreg Kroah-Hartman if (IS_ERR(usb_class->class)) { 8543104f1dSGreg Kroah-Hartman result = IS_ERR(usb_class->class); 8643104f1dSGreg Kroah-Hartman err("class_create failed for usb devices"); 8743104f1dSGreg Kroah-Hartman kfree(usb_class); 8843104f1dSGreg Kroah-Hartman usb_class = NULL; 8943104f1dSGreg Kroah-Hartman } 9043104f1dSGreg Kroah-Hartman 9143104f1dSGreg Kroah-Hartman exit: 9243104f1dSGreg Kroah-Hartman return result; 9343104f1dSGreg Kroah-Hartman } 9443104f1dSGreg Kroah-Hartman 9543104f1dSGreg Kroah-Hartman static void release_usb_class(struct kref *kref) 9643104f1dSGreg Kroah-Hartman { 9743104f1dSGreg Kroah-Hartman /* Ok, we cheat as we know we only have one usb_class */ 9843104f1dSGreg Kroah-Hartman class_destroy(usb_class->class); 9943104f1dSGreg Kroah-Hartman kfree(usb_class); 10043104f1dSGreg Kroah-Hartman usb_class = NULL; 10143104f1dSGreg Kroah-Hartman } 10243104f1dSGreg Kroah-Hartman 10343104f1dSGreg Kroah-Hartman static void destroy_usb_class(void) 10443104f1dSGreg Kroah-Hartman { 10543104f1dSGreg Kroah-Hartman if (usb_class) 10643104f1dSGreg Kroah-Hartman kref_put(&usb_class->kref, release_usb_class); 10743104f1dSGreg Kroah-Hartman } 1081da177e4SLinus Torvalds 1091da177e4SLinus Torvalds int usb_major_init(void) 1101da177e4SLinus Torvalds { 1111da177e4SLinus Torvalds int error; 1121da177e4SLinus Torvalds 1131da177e4SLinus Torvalds error = register_chrdev(USB_MAJOR, "usb", &usb_fops); 11443104f1dSGreg Kroah-Hartman if (error) 1151da177e4SLinus Torvalds err("unable to get major %d for usb devices", USB_MAJOR); 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds return error; 1181da177e4SLinus Torvalds } 1191da177e4SLinus Torvalds 1201da177e4SLinus Torvalds void usb_major_cleanup(void) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds unregister_chrdev(USB_MAJOR, "usb"); 1231da177e4SLinus Torvalds } 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds /** 1261da177e4SLinus Torvalds * usb_register_dev - register a USB device, and ask for a minor number 1271da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being registered 1281da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 1291da177e4SLinus Torvalds * 1301da177e4SLinus Torvalds * This should be called by all USB drivers that use the USB major number. 1311da177e4SLinus Torvalds * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be 1321da177e4SLinus Torvalds * dynamically allocated out of the list of available ones. If it is not 1331da177e4SLinus Torvalds * enabled, the minor number will be based on the next available free minor, 1341da177e4SLinus Torvalds * starting at the class_driver->minor_base. 1351da177e4SLinus Torvalds * 136d6e5bcf4SGreg Kroah-Hartman * This function also creates a usb class device in the sysfs tree. 1371da177e4SLinus Torvalds * 1381da177e4SLinus Torvalds * usb_deregister_dev() must be called when the driver is done with 1391da177e4SLinus Torvalds * the minor numbers given out by this function. 1401da177e4SLinus Torvalds * 1411da177e4SLinus Torvalds * Returns -EINVAL if something bad happens with trying to register a 1421da177e4SLinus Torvalds * device, and 0 on success. 1431da177e4SLinus Torvalds */ 1441da177e4SLinus Torvalds int usb_register_dev(struct usb_interface *intf, 1451da177e4SLinus Torvalds struct usb_class_driver *class_driver) 1461da177e4SLinus Torvalds { 1471da177e4SLinus Torvalds int retval = -EINVAL; 1481da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 1491da177e4SLinus Torvalds int minor = 0; 1501da177e4SLinus Torvalds char name[BUS_ID_SIZE]; 1511da177e4SLinus Torvalds char *temp; 1521da177e4SLinus Torvalds 1531da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 1541da177e4SLinus Torvalds /* 1551da177e4SLinus Torvalds * We don't care what the device tries to start at, we want to start 1561da177e4SLinus Torvalds * at zero to pack the devices into the smallest available space with 1571da177e4SLinus Torvalds * no holes in the minor range. 1581da177e4SLinus Torvalds */ 1591da177e4SLinus Torvalds minor_base = 0; 1601da177e4SLinus Torvalds #endif 1611da177e4SLinus Torvalds intf->minor = -1; 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds dbg ("looking for a minor, starting at %d", minor_base); 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds if (class_driver->fops == NULL) 1661da177e4SLinus Torvalds goto exit; 1671da177e4SLinus Torvalds 168*d4ead16fSAlan Stern down_write(&minor_rwsem); 1691da177e4SLinus Torvalds for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { 1701da177e4SLinus Torvalds if (usb_minors[minor]) 1711da177e4SLinus Torvalds continue; 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds usb_minors[minor] = class_driver->fops; 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds retval = 0; 1761da177e4SLinus Torvalds break; 1771da177e4SLinus Torvalds } 178*d4ead16fSAlan Stern up_write(&minor_rwsem); 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds if (retval) 1811da177e4SLinus Torvalds goto exit; 1821da177e4SLinus Torvalds 18343104f1dSGreg Kroah-Hartman retval = init_usb_class(); 18443104f1dSGreg Kroah-Hartman if (retval) 18543104f1dSGreg Kroah-Hartman goto exit; 18643104f1dSGreg Kroah-Hartman 1871da177e4SLinus Torvalds intf->minor = minor; 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds /* create a usb class device for this usb interface */ 190d6e5bcf4SGreg Kroah-Hartman snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base); 1911da177e4SLinus Torvalds temp = strrchr(name, '/'); 1921da177e4SLinus Torvalds if (temp && (temp[1] != 0x00)) 1931da177e4SLinus Torvalds ++temp; 1941da177e4SLinus Torvalds else 1951da177e4SLinus Torvalds temp = name; 1960873c764SGreg Kroah-Hartman intf->usb_dev = device_create(usb_class->class, &intf->dev, 1970873c764SGreg Kroah-Hartman MKDEV(USB_MAJOR, minor), "%s", temp); 1980873c764SGreg Kroah-Hartman if (IS_ERR(intf->usb_dev)) { 199*d4ead16fSAlan Stern down_write(&minor_rwsem); 2001da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 201*d4ead16fSAlan Stern up_write(&minor_rwsem); 2020873c764SGreg Kroah-Hartman retval = PTR_ERR(intf->usb_dev); 2031da177e4SLinus Torvalds } 2041da177e4SLinus Torvalds exit: 2051da177e4SLinus Torvalds return retval; 2061da177e4SLinus Torvalds } 2071da177e4SLinus Torvalds EXPORT_SYMBOL(usb_register_dev); 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds /** 2101da177e4SLinus Torvalds * usb_deregister_dev - deregister a USB device's dynamic minor. 2111da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being deregistered 2121da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 2131da177e4SLinus Torvalds * 2141da177e4SLinus Torvalds * Used in conjunction with usb_register_dev(). This function is called 2151da177e4SLinus Torvalds * when the USB driver is finished with the minor numbers gotten from a 2161da177e4SLinus Torvalds * call to usb_register_dev() (usually when the device is disconnected 2171da177e4SLinus Torvalds * from the system.) 2181da177e4SLinus Torvalds * 219d6e5bcf4SGreg Kroah-Hartman * This function also removes the usb class device from the sysfs tree. 2201da177e4SLinus Torvalds * 2211da177e4SLinus Torvalds * This should be called by all drivers that use the USB major number. 2221da177e4SLinus Torvalds */ 2231da177e4SLinus Torvalds void usb_deregister_dev(struct usb_interface *intf, 2241da177e4SLinus Torvalds struct usb_class_driver *class_driver) 2251da177e4SLinus Torvalds { 2261da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 2271da177e4SLinus Torvalds char name[BUS_ID_SIZE]; 2281da177e4SLinus Torvalds 2291da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 2301da177e4SLinus Torvalds minor_base = 0; 2311da177e4SLinus Torvalds #endif 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds if (intf->minor == -1) 2341da177e4SLinus Torvalds return; 2351da177e4SLinus Torvalds 2361da177e4SLinus Torvalds dbg ("removing %d minor", intf->minor); 2371da177e4SLinus Torvalds 238*d4ead16fSAlan Stern down_write(&minor_rwsem); 2391da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 240*d4ead16fSAlan Stern up_write(&minor_rwsem); 2411da177e4SLinus Torvalds 2421da177e4SLinus Torvalds snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); 2430873c764SGreg Kroah-Hartman device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); 2440873c764SGreg Kroah-Hartman intf->usb_dev = NULL; 2451da177e4SLinus Torvalds intf->minor = -1; 24643104f1dSGreg Kroah-Hartman destroy_usb_class(); 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds EXPORT_SYMBOL(usb_deregister_dev); 249