228 lines
5.8 KiB
C
228 lines
5.8 KiB
C
![]() |
/*
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* drivers/usb/file.c
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*
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* (C) Copyright Linus Torvalds 1999
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* (C) Copyright Johannes Erdfelt 1999-2001
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* (C) Copyright Andreas Gal 1999
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* (C) Copyright Gregory P. Smith 1999
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* (C) Copyright Deti Fliegl 1999 (new USB architecture)
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* (C) Copyright Randy Dunlap 2000
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* (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
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more docs, etc)
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* (C) Copyright Yggdrasil Computing, Inc. 2000
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* (usb_device_id matching changes by Adam J. Richter)
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* (C) Copyright Greg Kroah-Hartman 2002-2003
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*
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/devfs_fs_kernel.h>
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#include <linux/spinlock.h>
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#include <linux/errno.h>
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#ifdef CONFIG_USB_DEBUG
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#define DEBUG
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#else
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#undef DEBUG
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#endif
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#include <linux/usb.h>
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#define MAX_USB_MINORS 256
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static struct file_operations *usb_minors[MAX_USB_MINORS];
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static DEFINE_SPINLOCK(minor_lock);
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static int usb_open(struct inode * inode, struct file * file)
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{
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int minor = iminor(inode);
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struct file_operations *c;
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int err = -ENODEV;
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struct file_operations *old_fops, *new_fops = NULL;
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spin_lock (&minor_lock);
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c = usb_minors[minor];
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if (!c || !(new_fops = fops_get(c))) {
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spin_unlock(&minor_lock);
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return err;
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}
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spin_unlock(&minor_lock);
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old_fops = file->f_op;
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file->f_op = new_fops;
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/* Curiouser and curiouser... NULL ->open() as "no device" ? */
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if (file->f_op->open)
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err = file->f_op->open(inode,file);
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if (err) {
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fops_put(file->f_op);
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file->f_op = fops_get(old_fops);
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}
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fops_put(old_fops);
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return err;
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}
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static struct file_operations usb_fops = {
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.owner = THIS_MODULE,
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.open = usb_open,
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};
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static struct class_simple *usb_class;
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int usb_major_init(void)
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{
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int error;
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error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
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if (error) {
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err("unable to get major %d for usb devices", USB_MAJOR);
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goto out;
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}
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usb_class = class_simple_create(THIS_MODULE, "usb");
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if (IS_ERR(usb_class)) {
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err("class_simple_create failed for usb devices");
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unregister_chrdev(USB_MAJOR, "usb");
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goto out;
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}
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devfs_mk_dir("usb");
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out:
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return error;
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}
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void usb_major_cleanup(void)
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{
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class_simple_destroy(usb_class);
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devfs_remove("usb");
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unregister_chrdev(USB_MAJOR, "usb");
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}
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/**
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* usb_register_dev - register a USB device, and ask for a minor number
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* @intf: pointer to the usb_interface that is being registered
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* @class_driver: pointer to the usb_class_driver for this device
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*
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* This should be called by all USB drivers that use the USB major number.
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* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
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* dynamically allocated out of the list of available ones. If it is not
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* enabled, the minor number will be based on the next available free minor,
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* starting at the class_driver->minor_base.
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*
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* This function also creates the devfs file for the usb device, if devfs
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* is enabled, and creates a usb class device in the sysfs tree.
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*
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* usb_deregister_dev() must be called when the driver is done with
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* the minor numbers given out by this function.
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*
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* Returns -EINVAL if something bad happens with trying to register a
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* device, and 0 on success.
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*/
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int usb_register_dev(struct usb_interface *intf,
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struct usb_class_driver *class_driver)
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{
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int retval = -EINVAL;
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int minor_base = class_driver->minor_base;
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int minor = 0;
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char name[BUS_ID_SIZE];
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char *temp;
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#ifdef CONFIG_USB_DYNAMIC_MINORS
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/*
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* We don't care what the device tries to start at, we want to start
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* at zero to pack the devices into the smallest available space with
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* no holes in the minor range.
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*/
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minor_base = 0;
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#endif
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intf->minor = -1;
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dbg ("looking for a minor, starting at %d", minor_base);
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if (class_driver->fops == NULL)
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goto exit;
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spin_lock (&minor_lock);
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for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
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if (usb_minors[minor])
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continue;
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usb_minors[minor] = class_driver->fops;
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retval = 0;
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break;
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}
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spin_unlock (&minor_lock);
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if (retval)
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goto exit;
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intf->minor = minor;
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/* handle the devfs registration */
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snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
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devfs_mk_cdev(MKDEV(USB_MAJOR, minor), class_driver->mode, name);
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/* create a usb class device for this usb interface */
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temp = strrchr(name, '/');
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if (temp && (temp[1] != 0x00))
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++temp;
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else
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temp = name;
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intf->class_dev = class_simple_device_add(usb_class, MKDEV(USB_MAJOR, minor), &intf->dev, "%s", temp);
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if (IS_ERR(intf->class_dev)) {
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spin_lock (&minor_lock);
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usb_minors[intf->minor] = NULL;
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spin_unlock (&minor_lock);
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devfs_remove (name);
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retval = PTR_ERR(intf->class_dev);
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}
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exit:
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return retval;
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}
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EXPORT_SYMBOL(usb_register_dev);
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/**
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* usb_deregister_dev - deregister a USB device's dynamic minor.
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* @intf: pointer to the usb_interface that is being deregistered
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* @class_driver: pointer to the usb_class_driver for this device
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*
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* Used in conjunction with usb_register_dev(). This function is called
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* when the USB driver is finished with the minor numbers gotten from a
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* call to usb_register_dev() (usually when the device is disconnected
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* from the system.)
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*
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* This function also cleans up the devfs file for the usb device, if devfs
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* is enabled, and removes the usb class device from the sysfs tree.
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*
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* This should be called by all drivers that use the USB major number.
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*/
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void usb_deregister_dev(struct usb_interface *intf,
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struct usb_class_driver *class_driver)
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{
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int minor_base = class_driver->minor_base;
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char name[BUS_ID_SIZE];
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#ifdef CONFIG_USB_DYNAMIC_MINORS
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minor_base = 0;
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#endif
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if (intf->minor == -1)
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return;
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dbg ("removing %d minor", intf->minor);
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spin_lock (&minor_lock);
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usb_minors[intf->minor] = NULL;
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spin_unlock (&minor_lock);
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snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
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devfs_remove (name);
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class_simple_device_remove(MKDEV(USB_MAJOR, intf->minor));
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intf->class_dev = NULL;
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intf->minor = -1;
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}
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EXPORT_SYMBOL(usb_deregister_dev);
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