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/*

 * drivers/usb/file.c

 *

 * (C) Copyright Linus Torvalds 1999

 * (C) Copyright Johannes Erdfelt 1999-2001

 * (C) Copyright Andreas Gal 1999

 * (C) Copyright Gregory P. Smith 1999

 * (C) Copyright Deti Fliegl 1999 (new USB architecture)

 * (C) Copyright Randy Dunlap 2000

 * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,

        more docs, etc)

 * (C) Copyright Yggdrasil Computing, Inc. 2000

 *     (usb_device_id matching changes by Adam J. Richter)

 * (C) Copyright Greg Kroah-Hartman 2002-2003

 *

 */

#include <linuxcomp.h>

#include <linux/config.h>

#include <linux/module.h>

#include <linux/devfs_fs_kernel.h>

#include <linux/spinlock.h>

#include <linux/errno.h>

#ifdef CONFIG_USB_DEBUG

        #define DEBUG

#else

        #undef DEBUG

#endif

#include <linux/usb.h>

#define MAX_USB_MINORS  256

static struct file_operations *usb_minors[MAX_USB_MINORS];

static spinlock_t minor_lock = SPIN_LOCK_UNLOCKED;

static int usb_open(struct inode * inode, struct file * file)

{

        int minor = iminor(inode);

        struct file_operations *c;

        int err = -ENODEV;

        struct file_operations *old_fops, *new_fops = NULL;

        spin_lock (&minor_lock);

        c = usb_minors[minor];

        if (!c || !(new_fops = fops_get(c))) {

                spin_unlock(&minor_lock);

                return err;

        }

        spin_unlock(&minor_lock);

        old_fops = file->f_op;

        file->f_op = new_fops;

        /* Curiouser and curiouser... NULL ->open() as "no device" ? */

        if (file->f_op->open)

                err = file->f_op->open(inode,file);

        if (err) {

                fops_put(file->f_op);

                file->f_op = fops_get(old_fops);

        }

        fops_put(old_fops);

        return err;

}

static struct file_operations usb_fops = {

        .owner =        THIS_MODULE,

        .open =         usb_open,

};

static void release_usb_class_dev(struct class_device *class_dev)

{

        dbg("%s - %s", __FUNCTION__, class_dev->class_id);

        kfree(class_dev);

}

static struct class usb_class = {

        .name           = "usb",

        .release        = &release_usb_class_dev,

};

int usb_major_init(void)

{

        if (register_chrdev(USB_MAJOR, "usb", &usb_fops)) {

                err("unable to get major %d for usb devices", USB_MAJOR);

                return -EBUSY;

        }

        devfs_mk_dir("usb");

        class_register(&usb_class);

        return 0;

}

void usb_major_cleanup(void)

{

        class_unregister(&usb_class);

        devfs_remove("usb");

        unregister_chrdev(USB_MAJOR, "usb");

}

static ssize_t show_dev(struct class_device *class_dev, char *buf)

{

        int minor = (int)(long)class_get_devdata(class_dev);

        return print_dev_t(buf, MKDEV(USB_MAJOR, minor));

}

static CLASS_DEVICE_ATTR(dev, S_IRUGO, show_dev, NULL);

/**

 * usb_register_dev - register a USB device, and ask for a minor number

 * @intf: pointer to the usb_interface that is being registered

 * @class_driver: pointer to the usb_class_driver for this device

 *

 * This should be called by all USB drivers that use the USB major number.

 * If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be

 * dynamically allocated out of the list of available ones.  If it is not

 * enabled, the minor number will be based on the next available free minor,

 * starting at the class_driver->minor_base.

 *

 * This function also creates the devfs file for the usb device, if devfs

 * is enabled, and creates a usb class device in the sysfs tree.

 *

 * usb_deregister_dev() must be called when the driver is done with

 * the minor numbers given out by this function.

 *

 * Returns -EINVAL if something bad happens with trying to register a

 * device, and 0 on success.

 */

int usb_register_dev(struct usb_interface *intf,

                     struct usb_class_driver *class_driver)

{

        int retval = -EINVAL;

        int minor_base = class_driver->minor_base;

        int minor = 0;

        char name[BUS_ID_SIZE];

        struct class_device *class_dev;

        char *temp;

#ifdef CONFIG_USB_DYNAMIC_MINORS

        /*

         * We don't care what the device tries to start at, we want to start

         * at zero to pack the devices into the smallest available space with

         * no holes in the minor range.

         */

        minor_base = 0;

#endif

        intf->minor = -1;

        dbg ("looking for a minor, starting at %d", minor_base);

        if (class_driver->fops == NULL)

                goto exit;

        spin_lock (&minor_lock);

        for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {

                if (usb_minors[minor])

                        continue;

                usb_minors[minor] = class_driver->fops;

                retval = 0;

                break;

        }

        spin_unlock (&minor_lock);

        if (retval)

                goto exit;

        intf->minor = minor;

        /* handle the devfs registration */

        snprintf26(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);

        devfs_mk_cdev(MKDEV(USB_MAJOR, minor), class_driver->mode, name);

        /* create a usb class device for this usb interface */

        class_dev = kmalloc(sizeof(*class_dev), GFP_KERNEL);

        if (class_dev) {

                memset(class_dev, 0x00, sizeof(struct class_device));

                class_dev->class = &usb_class;

                class_dev->dev = &intf->dev;

                temp = strrchr(name, '/');

                if (temp && (temp[1] != 0x00))

                        ++temp;

                else

                        temp = name;

                snprintf26(class_dev->class_id, BUS_ID_SIZE, "%s", temp);

                class_set_devdata(class_dev, (void *)(long)intf->minor);

                class_device_register(class_dev);

                class_device_create_file(class_dev, &class_device_attr_dev);

                intf->class_dev = class_dev;

        }

exit:

        return retval;

}

EXPORT_SYMBOL(usb_register_dev);

/**

 * usb_deregister_dev - deregister a USB device's dynamic minor.

 * @intf: pointer to the usb_interface that is being deregistered

 * @class_driver: pointer to the usb_class_driver for this device

 *

 * Used in conjunction with usb_register_dev().  This function is called

 * when the USB driver is finished with the minor numbers gotten from a

 * call to usb_register_dev() (usually when the device is disconnected

 * from the system.)

 *

 * This function also cleans up the devfs file for the usb device, if devfs

 * is enabled, and removes the usb class device from the sysfs tree.

 *

 * This should be called by all drivers that use the USB major number.

 */

void usb_deregister_dev(struct usb_interface *intf,

                        struct usb_class_driver *class_driver)

{

        int minor_base = class_driver->minor_base;

        char name[BUS_ID_SIZE];

#ifdef CONFIG_USB_DYNAMIC_MINORS

        minor_base = 0;

#endif

        if (intf->minor == -1)

                return;

        dbg ("removing %d minor", intf->minor);

        spin_lock (&minor_lock);

        usb_minors[intf->minor] = NULL;

        spin_unlock (&minor_lock);

        snprintf26(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);

        devfs_remove (name);

        if (intf->class_dev) {

                class_device_unregister(intf->class_dev);

                intf->class_dev = NULL;

        }

        intf->minor = -1;

}

EXPORT_SYMBOL(usb_deregister_dev);