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> 20d4ead16fSAlan Stern #include <linux/rwsem.h> 21*5a0e3ad6STejun Heo #include <linux/slab.h> 2220613f24SJonathan Corbet #include <linux/smp_lock.h> 231da177e4SLinus Torvalds #include <linux/usb.h> 241da177e4SLinus Torvalds 256d5e8254SGreg KH #include "usb.h" 266d5e8254SGreg KH 271da177e4SLinus Torvalds #define MAX_USB_MINORS 256 2899ac48f5SArjan van de Ven static const struct file_operations *usb_minors[MAX_USB_MINORS]; 29d4ead16fSAlan Stern static DECLARE_RWSEM(minor_rwsem); 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds static int usb_open(struct inode * inode, struct file * file) 321da177e4SLinus Torvalds { 331da177e4SLinus Torvalds int minor = iminor(inode); 3499ac48f5SArjan van de Ven const struct file_operations *c; 351da177e4SLinus Torvalds int err = -ENODEV; 3699ac48f5SArjan van de Ven const struct file_operations *old_fops, *new_fops = NULL; 371da177e4SLinus Torvalds 38d4ead16fSAlan Stern down_read(&minor_rwsem); 391da177e4SLinus Torvalds c = usb_minors[minor]; 401da177e4SLinus Torvalds 41d4ead16fSAlan Stern if (!c || !(new_fops = fops_get(c))) 42d4ead16fSAlan Stern goto done; 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds old_fops = file->f_op; 451da177e4SLinus Torvalds file->f_op = new_fops; 461da177e4SLinus Torvalds /* Curiouser and curiouser... NULL ->open() as "no device" ? */ 471da177e4SLinus Torvalds if (file->f_op->open) 481da177e4SLinus Torvalds err = file->f_op->open(inode,file); 491da177e4SLinus Torvalds if (err) { 501da177e4SLinus Torvalds fops_put(file->f_op); 511da177e4SLinus Torvalds file->f_op = fops_get(old_fops); 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds fops_put(old_fops); 54d4ead16fSAlan Stern done: 55d4ead16fSAlan Stern up_read(&minor_rwsem); 561da177e4SLinus Torvalds return err; 571da177e4SLinus Torvalds } 581da177e4SLinus Torvalds 59066202ddSLuiz Fernando N. Capitulino static const struct file_operations usb_fops = { 601da177e4SLinus Torvalds .owner = THIS_MODULE, 611da177e4SLinus Torvalds .open = usb_open, 621da177e4SLinus Torvalds }; 631da177e4SLinus Torvalds 6443104f1dSGreg Kroah-Hartman static struct usb_class { 6543104f1dSGreg Kroah-Hartman struct kref kref; 6643104f1dSGreg Kroah-Hartman struct class *class; 6743104f1dSGreg Kroah-Hartman } *usb_class; 6843104f1dSGreg Kroah-Hartman 69e454cea2SKay Sievers static char *usb_devnode(struct device *dev, mode_t *mode) 70f7a386c5SKay Sievers { 71f7a386c5SKay Sievers struct usb_class_driver *drv; 72f7a386c5SKay Sievers 73f7a386c5SKay Sievers drv = dev_get_drvdata(dev); 74e454cea2SKay Sievers if (!drv || !drv->devnode) 75f7a386c5SKay Sievers return NULL; 76e454cea2SKay Sievers return drv->devnode(dev, mode); 77f7a386c5SKay Sievers } 78f7a386c5SKay Sievers 7943104f1dSGreg Kroah-Hartman static int init_usb_class(void) 8043104f1dSGreg Kroah-Hartman { 8143104f1dSGreg Kroah-Hartman int result = 0; 8243104f1dSGreg Kroah-Hartman 8343104f1dSGreg Kroah-Hartman if (usb_class != NULL) { 8443104f1dSGreg Kroah-Hartman kref_get(&usb_class->kref); 8543104f1dSGreg Kroah-Hartman goto exit; 8643104f1dSGreg Kroah-Hartman } 8743104f1dSGreg Kroah-Hartman 8843104f1dSGreg Kroah-Hartman usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL); 8943104f1dSGreg Kroah-Hartman if (!usb_class) { 9043104f1dSGreg Kroah-Hartman result = -ENOMEM; 9143104f1dSGreg Kroah-Hartman goto exit; 9243104f1dSGreg Kroah-Hartman } 9343104f1dSGreg Kroah-Hartman 9443104f1dSGreg Kroah-Hartman kref_init(&usb_class->kref); 9543104f1dSGreg Kroah-Hartman usb_class->class = class_create(THIS_MODULE, "usb"); 9643104f1dSGreg Kroah-Hartman if (IS_ERR(usb_class->class)) { 9743104f1dSGreg Kroah-Hartman result = IS_ERR(usb_class->class); 9869a85942SGreg Kroah-Hartman printk(KERN_ERR "class_create failed for usb devices\n"); 9943104f1dSGreg Kroah-Hartman kfree(usb_class); 10043104f1dSGreg Kroah-Hartman usb_class = NULL; 101ed7487c2SDan Carpenter goto exit; 10243104f1dSGreg Kroah-Hartman } 103e454cea2SKay Sievers usb_class->class->devnode = usb_devnode; 10443104f1dSGreg Kroah-Hartman 10543104f1dSGreg Kroah-Hartman exit: 10643104f1dSGreg Kroah-Hartman return result; 10743104f1dSGreg Kroah-Hartman } 10843104f1dSGreg Kroah-Hartman 10943104f1dSGreg Kroah-Hartman static void release_usb_class(struct kref *kref) 11043104f1dSGreg Kroah-Hartman { 11143104f1dSGreg Kroah-Hartman /* Ok, we cheat as we know we only have one usb_class */ 11243104f1dSGreg Kroah-Hartman class_destroy(usb_class->class); 11343104f1dSGreg Kroah-Hartman kfree(usb_class); 11443104f1dSGreg Kroah-Hartman usb_class = NULL; 11543104f1dSGreg Kroah-Hartman } 11643104f1dSGreg Kroah-Hartman 11743104f1dSGreg Kroah-Hartman static void destroy_usb_class(void) 11843104f1dSGreg Kroah-Hartman { 11943104f1dSGreg Kroah-Hartman if (usb_class) 12043104f1dSGreg Kroah-Hartman kref_put(&usb_class->kref, release_usb_class); 12143104f1dSGreg Kroah-Hartman } 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds int usb_major_init(void) 1241da177e4SLinus Torvalds { 1251da177e4SLinus Torvalds int error; 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds error = register_chrdev(USB_MAJOR, "usb", &usb_fops); 12843104f1dSGreg Kroah-Hartman if (error) 12969a85942SGreg Kroah-Hartman printk(KERN_ERR "Unable to get major %d for usb devices\n", 13069a85942SGreg Kroah-Hartman USB_MAJOR); 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds return error; 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds void usb_major_cleanup(void) 1361da177e4SLinus Torvalds { 1371da177e4SLinus Torvalds unregister_chrdev(USB_MAJOR, "usb"); 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds /** 1411da177e4SLinus Torvalds * usb_register_dev - register a USB device, and ask for a minor number 1421da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being registered 1431da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 1441da177e4SLinus Torvalds * 1451da177e4SLinus Torvalds * This should be called by all USB drivers that use the USB major number. 1461da177e4SLinus Torvalds * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be 1471da177e4SLinus Torvalds * dynamically allocated out of the list of available ones. If it is not 1481da177e4SLinus Torvalds * enabled, the minor number will be based on the next available free minor, 1491da177e4SLinus Torvalds * starting at the class_driver->minor_base. 1501da177e4SLinus Torvalds * 151d6e5bcf4SGreg Kroah-Hartman * This function also creates a usb class device in the sysfs tree. 1521da177e4SLinus Torvalds * 1531da177e4SLinus Torvalds * usb_deregister_dev() must be called when the driver is done with 1541da177e4SLinus Torvalds * the minor numbers given out by this function. 1551da177e4SLinus Torvalds * 1561da177e4SLinus Torvalds * Returns -EINVAL if something bad happens with trying to register a 1571da177e4SLinus Torvalds * device, and 0 on success. 1581da177e4SLinus Torvalds */ 1591da177e4SLinus Torvalds int usb_register_dev(struct usb_interface *intf, 1601da177e4SLinus Torvalds struct usb_class_driver *class_driver) 1611da177e4SLinus Torvalds { 1621da177e4SLinus Torvalds int retval = -EINVAL; 1631da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 1641da177e4SLinus Torvalds int minor = 0; 1657071a3ceSKay Sievers char name[20]; 1661da177e4SLinus Torvalds char *temp; 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 1691da177e4SLinus Torvalds /* 1701da177e4SLinus Torvalds * We don't care what the device tries to start at, we want to start 1711da177e4SLinus Torvalds * at zero to pack the devices into the smallest available space with 1721da177e4SLinus Torvalds * no holes in the minor range. 1731da177e4SLinus Torvalds */ 1741da177e4SLinus Torvalds minor_base = 0; 1751da177e4SLinus Torvalds #endif 1761da177e4SLinus Torvalds intf->minor = -1; 1771da177e4SLinus Torvalds 1781da177e4SLinus Torvalds dbg ("looking for a minor, starting at %d", minor_base); 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds if (class_driver->fops == NULL) 1811da177e4SLinus Torvalds goto exit; 1821da177e4SLinus Torvalds 183d4ead16fSAlan Stern down_write(&minor_rwsem); 1841da177e4SLinus Torvalds for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { 1851da177e4SLinus Torvalds if (usb_minors[minor]) 1861da177e4SLinus Torvalds continue; 1871da177e4SLinus Torvalds 1881da177e4SLinus Torvalds usb_minors[minor] = class_driver->fops; 1891da177e4SLinus Torvalds 1901da177e4SLinus Torvalds retval = 0; 1911da177e4SLinus Torvalds break; 1921da177e4SLinus Torvalds } 193d4ead16fSAlan Stern up_write(&minor_rwsem); 1941da177e4SLinus Torvalds 1951da177e4SLinus Torvalds if (retval) 1961da177e4SLinus Torvalds goto exit; 1971da177e4SLinus Torvalds 19843104f1dSGreg Kroah-Hartman retval = init_usb_class(); 19943104f1dSGreg Kroah-Hartman if (retval) 20043104f1dSGreg Kroah-Hartman goto exit; 20143104f1dSGreg Kroah-Hartman 2021da177e4SLinus Torvalds intf->minor = minor; 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds /* create a usb class device for this usb interface */ 2057071a3ceSKay Sievers snprintf(name, sizeof(name), class_driver->name, minor - minor_base); 2061da177e4SLinus Torvalds temp = strrchr(name, '/'); 2077071a3ceSKay Sievers if (temp && (temp[1] != '\0')) 2081da177e4SLinus Torvalds ++temp; 2091da177e4SLinus Torvalds else 2101da177e4SLinus Torvalds temp = name; 211b0b090e5SGreg Kroah-Hartman intf->usb_dev = device_create(usb_class->class, &intf->dev, 212f7a386c5SKay Sievers MKDEV(USB_MAJOR, minor), class_driver, 213bc00bc92SGreg Kroah-Hartman "%s", temp); 2140873c764SGreg Kroah-Hartman if (IS_ERR(intf->usb_dev)) { 215d4ead16fSAlan Stern down_write(&minor_rwsem); 2161da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 217d4ead16fSAlan Stern up_write(&minor_rwsem); 2180873c764SGreg Kroah-Hartman retval = PTR_ERR(intf->usb_dev); 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds exit: 2211da177e4SLinus Torvalds return retval; 2221da177e4SLinus Torvalds } 223782e70c6SGreg Kroah-Hartman EXPORT_SYMBOL_GPL(usb_register_dev); 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds /** 2261da177e4SLinus Torvalds * usb_deregister_dev - deregister a USB device's dynamic minor. 2271da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being deregistered 2281da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 2291da177e4SLinus Torvalds * 2301da177e4SLinus Torvalds * Used in conjunction with usb_register_dev(). This function is called 2311da177e4SLinus Torvalds * when the USB driver is finished with the minor numbers gotten from a 2321da177e4SLinus Torvalds * call to usb_register_dev() (usually when the device is disconnected 2331da177e4SLinus Torvalds * from the system.) 2341da177e4SLinus Torvalds * 235d6e5bcf4SGreg Kroah-Hartman * This function also removes the usb class device from the sysfs tree. 2361da177e4SLinus Torvalds * 2371da177e4SLinus Torvalds * This should be called by all drivers that use the USB major number. 2381da177e4SLinus Torvalds */ 2391da177e4SLinus Torvalds void usb_deregister_dev(struct usb_interface *intf, 2401da177e4SLinus Torvalds struct usb_class_driver *class_driver) 2411da177e4SLinus Torvalds { 2421da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 2437071a3ceSKay Sievers char name[20]; 2441da177e4SLinus Torvalds 2451da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 2461da177e4SLinus Torvalds minor_base = 0; 2471da177e4SLinus Torvalds #endif 2481da177e4SLinus Torvalds 2491da177e4SLinus Torvalds if (intf->minor == -1) 2501da177e4SLinus Torvalds return; 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds dbg ("removing %d minor", intf->minor); 2531da177e4SLinus Torvalds 254d4ead16fSAlan Stern down_write(&minor_rwsem); 2551da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 256d4ead16fSAlan Stern up_write(&minor_rwsem); 2571da177e4SLinus Torvalds 2587071a3ceSKay Sievers snprintf(name, sizeof(name), class_driver->name, intf->minor - minor_base); 2590873c764SGreg Kroah-Hartman device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor)); 2600873c764SGreg Kroah-Hartman intf->usb_dev = NULL; 2611da177e4SLinus Torvalds intf->minor = -1; 26243104f1dSGreg Kroah-Hartman destroy_usb_class(); 2631da177e4SLinus Torvalds } 264782e70c6SGreg Kroah-Hartman EXPORT_SYMBOL_GPL(usb_deregister_dev); 265