/*
* 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 <linux/config.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include "usb.h"
#define MAX_USB_MINORS 256
static struct file_operations *usb_minors[MAX_USB_MINORS];
static DEFINE_SPINLOCK(minor_lock);
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 struct class *usb_class;
int usb_major_init(void)
{
int error;
error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
if (error) {
err("unable to get major %d for usb devices", USB_MAJOR);
goto out;
}
usb_class = class_create(THIS_MODULE, "usb");
if (IS_ERR(usb_class)) {
error = PTR_ERR(usb_class);
err("class_create failed for usb devices");
unregister_chrdev(USB_MAJOR, "usb");
goto out;
}
out:
return error;
}
void usb_major_cleanup(void)
{
class_destroy(usb_class);
unregister_chrdev(USB_MAJOR, "usb");
}
/**
* 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 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];
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;
/* create a usb class device for this usb interface */
snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
temp = strrchr(name, '/');
if (temp && (temp[1] != 0x00))
++temp;
else
temp = name;
intf->class_dev = class_device_create(usb_class, NULL,
MKDEV(USB_MAJOR, minor),
&intf->dev, "%s", temp);
if (IS_ERR(intf->class_dev)) {
spin_lock (&minor_lock);
usb_minors[intf->minor] = NULL;
spin_unlock (&minor_lock);
retval = PTR_ERR(intf->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 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);
snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
class_device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor));
intf->class_dev = NULL;
intf->minor = -1;
}
EXPORT_SYMBOL(usb_deregister_dev);
