1aa1f3bb5SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 21da177e4SLinus Torvalds /* 3f30c2269SUwe Zeisberger * drivers/usb/core/file.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * (C) Copyright Linus Torvalds 1999 61da177e4SLinus Torvalds * (C) Copyright Johannes Erdfelt 1999-2001 71da177e4SLinus Torvalds * (C) Copyright Andreas Gal 1999 81da177e4SLinus Torvalds * (C) Copyright Gregory P. Smith 1999 91da177e4SLinus Torvalds * (C) Copyright Deti Fliegl 1999 (new USB architecture) 101da177e4SLinus Torvalds * (C) Copyright Randy Dunlap 2000 111da177e4SLinus Torvalds * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id, 12469271f8SMatthias Beyer * more docs, etc) 131da177e4SLinus Torvalds * (C) Copyright Yggdrasil Computing, Inc. 2000 141da177e4SLinus Torvalds * (usb_device_id matching changes by Adam J. Richter) 151da177e4SLinus Torvalds * (C) Copyright Greg Kroah-Hartman 2002-2003 161da177e4SLinus Torvalds * 17b65fba3dSGreg Kroah-Hartman * Released under the GPLv2 only. 181da177e4SLinus Torvalds */ 191da177e4SLinus Torvalds 201da177e4SLinus Torvalds #include <linux/module.h> 211da177e4SLinus Torvalds #include <linux/errno.h> 22d4ead16fSAlan Stern #include <linux/rwsem.h> 235a0e3ad6STejun Heo #include <linux/slab.h> 24f8868ed0SAndy Shevchenko #include <linux/string.h> 251da177e4SLinus Torvalds #include <linux/usb.h> 261da177e4SLinus Torvalds 276d5e8254SGreg KH #include "usb.h" 286d5e8254SGreg KH 291da177e4SLinus Torvalds #define MAX_USB_MINORS 256 3099ac48f5SArjan van de Ven static const struct file_operations *usb_minors[MAX_USB_MINORS]; 31d4ead16fSAlan Stern static DECLARE_RWSEM(minor_rwsem); 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds static int usb_open(struct inode *inode, struct file *file) 341da177e4SLinus Torvalds { 351da177e4SLinus Torvalds int err = -ENODEV; 36e84f9e57SAl Viro const struct file_operations *new_fops; 371da177e4SLinus Torvalds 38d4ead16fSAlan Stern down_read(&minor_rwsem); 39e84f9e57SAl Viro new_fops = fops_get(usb_minors[iminor(inode)]); 401da177e4SLinus Torvalds 41e84f9e57SAl Viro if (!new_fops) 42d4ead16fSAlan Stern goto done; 431da177e4SLinus Torvalds 44e84f9e57SAl Viro replace_fops(file, new_fops); 451da177e4SLinus Torvalds /* Curiouser and curiouser... NULL ->open() as "no device" ? */ 461da177e4SLinus Torvalds if (file->f_op->open) 471da177e4SLinus Torvalds err = file->f_op->open(inode, file); 48d4ead16fSAlan Stern done: 49d4ead16fSAlan Stern up_read(&minor_rwsem); 501da177e4SLinus Torvalds return err; 511da177e4SLinus Torvalds } 521da177e4SLinus Torvalds 53066202ddSLuiz Fernando N. Capitulino static const struct file_operations usb_fops = { 541da177e4SLinus Torvalds .owner = THIS_MODULE, 551da177e4SLinus Torvalds .open = usb_open, 566038f373SArnd Bergmann .llseek = noop_llseek, 571da177e4SLinus Torvalds }; 581da177e4SLinus Torvalds 59ff62b8e6SGreg Kroah-Hartman static char *usb_devnode(const struct device *dev, umode_t *mode) 60f7a386c5SKay Sievers { 61f7a386c5SKay Sievers struct usb_class_driver *drv; 62f7a386c5SKay Sievers 63f7a386c5SKay Sievers drv = dev_get_drvdata(dev); 64e454cea2SKay Sievers if (!drv || !drv->devnode) 65f7a386c5SKay Sievers return NULL; 66e454cea2SKay Sievers return drv->devnode(dev, mode); 67f7a386c5SKay Sievers } 68f7a386c5SKay Sievers 69*015fbddeSIvan Orlov const struct class usbmisc_class = { 70*015fbddeSIvan Orlov .name = "usbmisc", 71*015fbddeSIvan Orlov .devnode = usb_devnode, 72*015fbddeSIvan Orlov }; 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds int usb_major_init(void) 751da177e4SLinus Torvalds { 761da177e4SLinus Torvalds int error; 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds error = register_chrdev(USB_MAJOR, "usb", &usb_fops); 7943104f1dSGreg Kroah-Hartman if (error) 8069a85942SGreg Kroah-Hartman printk(KERN_ERR "Unable to get major %d for usb devices\n", 8169a85942SGreg Kroah-Hartman USB_MAJOR); 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds return error; 841da177e4SLinus Torvalds } 851da177e4SLinus Torvalds 861da177e4SLinus Torvalds void usb_major_cleanup(void) 871da177e4SLinus Torvalds { 881da177e4SLinus Torvalds unregister_chrdev(USB_MAJOR, "usb"); 891da177e4SLinus Torvalds } 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /** 921da177e4SLinus Torvalds * usb_register_dev - register a USB device, and ask for a minor number 931da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being registered 941da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 951da177e4SLinus Torvalds * 961da177e4SLinus Torvalds * This should be called by all USB drivers that use the USB major number. 971da177e4SLinus Torvalds * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be 981da177e4SLinus Torvalds * dynamically allocated out of the list of available ones. If it is not 991da177e4SLinus Torvalds * enabled, the minor number will be based on the next available free minor, 1001da177e4SLinus Torvalds * starting at the class_driver->minor_base. 1011da177e4SLinus Torvalds * 102d6e5bcf4SGreg Kroah-Hartman * This function also creates a usb class device in the sysfs tree. 1031da177e4SLinus Torvalds * 1041da177e4SLinus Torvalds * usb_deregister_dev() must be called when the driver is done with 1051da177e4SLinus Torvalds * the minor numbers given out by this function. 1061da177e4SLinus Torvalds * 107626f090cSYacine Belkadi * Return: -EINVAL if something bad happens with trying to register a 1081da177e4SLinus Torvalds * device, and 0 on success. 1091da177e4SLinus Torvalds */ 1101da177e4SLinus Torvalds int usb_register_dev(struct usb_interface *intf, 1111da177e4SLinus Torvalds struct usb_class_driver *class_driver) 1121da177e4SLinus Torvalds { 113*015fbddeSIvan Orlov int retval = 0; 1141da177e4SLinus Torvalds int minor_base = class_driver->minor_base; 1150026e005SAlan Stern int minor; 1167071a3ceSKay Sievers char name[20]; 1171da177e4SLinus Torvalds 1181da177e4SLinus Torvalds #ifdef CONFIG_USB_DYNAMIC_MINORS 1191da177e4SLinus Torvalds /* 1201da177e4SLinus Torvalds * We don't care what the device tries to start at, we want to start 1211da177e4SLinus Torvalds * at zero to pack the devices into the smallest available space with 1221da177e4SLinus Torvalds * no holes in the minor range. 1231da177e4SLinus Torvalds */ 1241da177e4SLinus Torvalds minor_base = 0; 1251da177e4SLinus Torvalds #endif 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds if (class_driver->fops == NULL) 1280026e005SAlan Stern return -EINVAL; 1290026e005SAlan Stern if (intf->minor >= 0) 1300026e005SAlan Stern return -EADDRINUSE; 1310026e005SAlan Stern 132079d440eSGreg Kroah-Hartman dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base); 1331da177e4SLinus Torvalds 134d4ead16fSAlan Stern down_write(&minor_rwsem); 1351da177e4SLinus Torvalds for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) { 1361da177e4SLinus Torvalds if (usb_minors[minor]) 1371da177e4SLinus Torvalds continue; 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds usb_minors[minor] = class_driver->fops; 1400026e005SAlan Stern intf->minor = minor; 1411da177e4SLinus Torvalds break; 1421da177e4SLinus Torvalds } 143303911cfSAlan Stern if (intf->minor < 0) { 144d4ead16fSAlan Stern up_write(&minor_rwsem); 1450026e005SAlan Stern return -EXFULL; 146303911cfSAlan Stern } 1471da177e4SLinus Torvalds 1481da177e4SLinus Torvalds /* create a usb class device for this usb interface */ 1497071a3ceSKay Sievers snprintf(name, sizeof(name), class_driver->name, minor - minor_base); 150*015fbddeSIvan Orlov intf->usb_dev = device_create(&usbmisc_class, &intf->dev, 151f7a386c5SKay Sievers MKDEV(USB_MAJOR, minor), class_driver, 152f8868ed0SAndy Shevchenko "%s", kbasename(name)); 1530873c764SGreg Kroah-Hartman if (IS_ERR(intf->usb_dev)) { 1540026e005SAlan Stern usb_minors[minor] = NULL; 1550026e005SAlan Stern intf->minor = -1; 1560873c764SGreg Kroah-Hartman retval = PTR_ERR(intf->usb_dev); 1571da177e4SLinus Torvalds } 158303911cfSAlan Stern up_write(&minor_rwsem); 1591da177e4SLinus Torvalds return retval; 1601da177e4SLinus Torvalds } 161782e70c6SGreg Kroah-Hartman EXPORT_SYMBOL_GPL(usb_register_dev); 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds /** 1641da177e4SLinus Torvalds * usb_deregister_dev - deregister a USB device's dynamic minor. 1651da177e4SLinus Torvalds * @intf: pointer to the usb_interface that is being deregistered 1661da177e4SLinus Torvalds * @class_driver: pointer to the usb_class_driver for this device 1671da177e4SLinus Torvalds * 1681da177e4SLinus Torvalds * Used in conjunction with usb_register_dev(). This function is called 1691da177e4SLinus Torvalds * when the USB driver is finished with the minor numbers gotten from a 1701da177e4SLinus Torvalds * call to usb_register_dev() (usually when the device is disconnected 1711da177e4SLinus Torvalds * from the system.) 1721da177e4SLinus Torvalds * 173d6e5bcf4SGreg Kroah-Hartman * This function also removes the usb class device from the sysfs tree. 1741da177e4SLinus Torvalds * 1751da177e4SLinus Torvalds * This should be called by all drivers that use the USB major number. 1761da177e4SLinus Torvalds */ 1771da177e4SLinus Torvalds void usb_deregister_dev(struct usb_interface *intf, 1781da177e4SLinus Torvalds struct usb_class_driver *class_driver) 1791da177e4SLinus Torvalds { 1801da177e4SLinus Torvalds if (intf->minor == -1) 1811da177e4SLinus Torvalds return; 1821da177e4SLinus Torvalds 183079d440eSGreg Kroah-Hartman dev_dbg(&intf->dev, "removing %d minor\n", intf->minor); 184*015fbddeSIvan Orlov device_destroy(&usbmisc_class, MKDEV(USB_MAJOR, intf->minor)); 1851da177e4SLinus Torvalds 186d4ead16fSAlan Stern down_write(&minor_rwsem); 1871da177e4SLinus Torvalds usb_minors[intf->minor] = NULL; 188d4ead16fSAlan Stern up_write(&minor_rwsem); 1891da177e4SLinus Torvalds 1900873c764SGreg Kroah-Hartman intf->usb_dev = NULL; 1911da177e4SLinus Torvalds intf->minor = -1; 1921da177e4SLinus Torvalds } 193782e70c6SGreg Kroah-Hartman EXPORT_SYMBOL_GPL(usb_deregister_dev); 194