[mirror_ubuntu-zesty-kernel.git] / drivers / usb / core / file.c

/*
 * 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 const 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);
	const struct file_operations *c;
	int err = -ENODEV;
	const 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 usb_class {
	struct kref kref;
	struct class *class;
} *usb_class;

static int init_usb_class(void)
{
	int result = 0;

	if (usb_class != NULL) {
		kref_get(&usb_class->kref);
		goto exit;
	}

	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
	if (!usb_class) {
		result = -ENOMEM;
		goto exit;
	}

	kref_init(&usb_class->kref);
	usb_class->class = class_create(THIS_MODULE, "usb");
	if (IS_ERR(usb_class->class)) {
		result = IS_ERR(usb_class->class);
		err("class_create failed for usb devices");
		kfree(usb_class);
		usb_class = NULL;
	}

exit:
	return result;
}

static void release_usb_class(struct kref *kref)
{
	/* Ok, we cheat as we know we only have one usb_class */
	class_destroy(usb_class->class);
	kfree(usb_class);
	usb_class = NULL;
}

static void destroy_usb_class(void)
{
	if (usb_class)
		kref_put(&usb_class->kref, release_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);

	return error;
}

void usb_major_cleanup(void)
{
	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;

	retval = init_usb_class();
	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->usb_dev = device_create(usb_class->class, &intf->dev,
				      MKDEV(USB_MAJOR, minor), "%s", temp);
	if (IS_ERR(intf->usb_dev)) {
		spin_lock (&minor_lock);
		usb_minors[intf->minor] = NULL;
		spin_unlock (&minor_lock);
		retval = PTR_ERR(intf->usb_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);
	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
	intf->usb_dev = NULL;
	intf->minor = -1;
	destroy_usb_class();
}
EXPORT_SYMBOL(usb_deregister_dev);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/usb/file.c
	3	*
	4	* (C) Copyright Linus Torvalds 1999
	5	* (C) Copyright Johannes Erdfelt 1999-2001
	6	* (C) Copyright Andreas Gal 1999
	7	* (C) Copyright Gregory P. Smith 1999
	8	* (C) Copyright Deti Fliegl 1999 (new USB architecture)
	9	* (C) Copyright Randy Dunlap 2000
	10	* (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
	11	more docs, etc)
	12	* (C) Copyright Yggdrasil Computing, Inc. 2000
	13	* (usb_device_id matching changes by Adam J. Richter)
	14	* (C) Copyright Greg Kroah-Hartman 2002-2003
	15	*
	16	*/
	17
	18	#include <linux/config.h>
	19	#include <linux/module.h>
1da177e4 LT	20	#include <linux/spinlock.h>
1da177e4 LT	21	#include <linux/errno.h>
1da177e4 LT	22	#include <linux/usb.h>
1da177e4 LT	23
6d5e8254 GKH	24	#include "usb.h"
6d5e8254 GKH	25
1da177e4	26	#define MAX_USB_MINORS 256
99ac48f5	27	static const struct file_operations *usb_minors[MAX_USB_MINORS];
1da177e4 LT	28	static DEFINE_SPINLOCK(minor_lock);
	29
	30	static int usb_open(struct inode * inode, struct file * file)
	31	{
	32	int minor = iminor(inode);
99ac48f5	33	const struct file_operations *c;
1da177e4	34	int err = -ENODEV;
99ac48f5	35	const struct file_operations old_fops, new_fops = NULL;
1da177e4 LT	36
	37	spin_lock (&minor_lock);
	38	c = usb_minors[minor];
	39
	40	if (!c \|\| !(new_fops = fops_get(c))) {
	41	spin_unlock(&minor_lock);
	42	return err;
	43	}
	44	spin_unlock(&minor_lock);
	45
	46	old_fops = file->f_op;
	47	file->f_op = new_fops;
	48	/* Curiouser and curiouser... NULL ->open() as "no device" ? */
	49	if (file->f_op->open)
	50	err = file->f_op->open(inode,file);
	51	if (err) {
	52	fops_put(file->f_op);
	53	file->f_op = fops_get(old_fops);
	54	}
	55	fops_put(old_fops);
	56	return err;
	57	}
	58
	59	static struct file_operations usb_fops = {
	60	.owner = THIS_MODULE,
	61	.open = usb_open,
	62	};
	63
43104f1d GKH	64	static struct usb_class {
	65	struct kref kref;
	66	struct class *class;
	67	} *usb_class;
1da177e4	68
43104f1d	69	static int init_usb_class(void)
1da177e4	70	{
43104f1d	71	int result = 0;
1da177e4	72
43104f1d GKH	73	if (usb_class != NULL) {
	74	kref_get(&usb_class->kref);
	75	goto exit;
	76	}
	77
	78	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
	79	if (!usb_class) {
	80	result = -ENOMEM;
	81	goto exit;
1da177e4 LT	82	}
1da177e4 LT	83
43104f1d GKH	84	kref_init(&usb_class->kref);
	85	usb_class->class = class_create(THIS_MODULE, "usb");
	86	if (IS_ERR(usb_class->class)) {
	87	result = IS_ERR(usb_class->class);
56b22935	88	err("class_create failed for usb devices");
43104f1d GKH	89	kfree(usb_class);
43104f1d GKH	90	usb_class = NULL;
1da177e4 LT	91	}
1da177e4 LT	92
43104f1d GKH	93	exit:
	94	return result;
	95	}
	96
	97	static void release_usb_class(struct kref *kref)
	98	{
	99	/* Ok, we cheat as we know we only have one usb_class */
	100	class_destroy(usb_class->class);
	101	kfree(usb_class);
	102	usb_class = NULL;
	103	}
	104
	105	static void destroy_usb_class(void)
	106	{
	107	if (usb_class)
	108	kref_put(&usb_class->kref, release_usb_class);
	109	}
	110
	111	int usb_major_init(void)
	112	{
	113	int error;
	114
	115	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
	116	if (error)
	117	err("unable to get major %d for usb devices", USB_MAJOR);
	118
1da177e4 LT	119	return error;
	120	}
	121
	122	void usb_major_cleanup(void)
	123	{
1da177e4 LT	124	unregister_chrdev(USB_MAJOR, "usb");
	125	}
	126
	127	/**
	128	* usb_register_dev - register a USB device, and ask for a minor number
	129	* @intf: pointer to the usb_interface that is being registered
	130	* @class_driver: pointer to the usb_class_driver for this device
	131	*
	132	* This should be called by all USB drivers that use the USB major number.
	133	* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
	134	* dynamically allocated out of the list of available ones. If it is not
	135	* enabled, the minor number will be based on the next available free minor,
	136	* starting at the class_driver->minor_base.
	137	*
d6e5bcf4	138	* This function also creates a usb class device in the sysfs tree.
1da177e4 LT	139	*
	140	* usb_deregister_dev() must be called when the driver is done with
	141	* the minor numbers given out by this function.
	142	*
	143	* Returns -EINVAL if something bad happens with trying to register a
	144	* device, and 0 on success.
	145	*/
	146	int usb_register_dev(struct usb_interface *intf,
	147	struct usb_class_driver *class_driver)
	148	{
	149	int retval = -EINVAL;
	150	int minor_base = class_driver->minor_base;
	151	int minor = 0;
	152	char name[BUS_ID_SIZE];
	153	char *temp;
	154
	155	#ifdef CONFIG_USB_DYNAMIC_MINORS
	156	/*
	157	* We don't care what the device tries to start at, we want to start
	158	* at zero to pack the devices into the smallest available space with
	159	* no holes in the minor range.
	160	*/
	161	minor_base = 0;
	162	#endif
	163	intf->minor = -1;
	164
	165	dbg ("looking for a minor, starting at %d", minor_base);
	166
	167	if (class_driver->fops == NULL)
	168	goto exit;
	169
	170	spin_lock (&minor_lock);
	171	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
	172	if (usb_minors[minor])
	173	continue;
	174
	175	usb_minors[minor] = class_driver->fops;
	176
	177	retval = 0;
	178	break;
	179	}
	180	spin_unlock (&minor_lock);
	181
43104f1d GKH	182	if (retval)
	183	goto exit;
	184
	185	retval = init_usb_class();
1da177e4 LT	186	if (retval)
	187	goto exit;
	188
	189	intf->minor = minor;
	190
1da177e4	191	/* create a usb class device for this usb interface */
d6e5bcf4	192	snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
1da177e4 LT	193	temp = strrchr(name, '/');
	194	if (temp && (temp[1] != 0x00))
	195	++temp;
	196	else
	197	temp = name;
43104f1d	198	intf->usb_dev = device_create(usb_class->class, &intf->dev,
bd009496 GKH	199	MKDEV(USB_MAJOR, minor), "%s", temp);
bd009496 GKH	200	if (IS_ERR(intf->usb_dev)) {
1da177e4 LT	201	spin_lock (&minor_lock);
	202	usb_minors[intf->minor] = NULL;
	203	spin_unlock (&minor_lock);
bd009496	204	retval = PTR_ERR(intf->usb_dev);
1da177e4 LT	205	}
	206	exit:
	207	return retval;
	208	}
	209	EXPORT_SYMBOL(usb_register_dev);
	210
	211	/**
	212	* usb_deregister_dev - deregister a USB device's dynamic minor.
	213	* @intf: pointer to the usb_interface that is being deregistered
	214	* @class_driver: pointer to the usb_class_driver for this device
	215	*
	216	* Used in conjunction with usb_register_dev(). This function is called
	217	* when the USB driver is finished with the minor numbers gotten from a
	218	* call to usb_register_dev() (usually when the device is disconnected
	219	* from the system.)
	220	*
d6e5bcf4 GKH	221	* This function also removes the usb class device from the sysfs tree.
d6e5bcf4 GKH	222	*
1da177e4 LT	223	* This should be called by all drivers that use the USB major number.
	224	*/
	225	void usb_deregister_dev(struct usb_interface *intf,
	226	struct usb_class_driver *class_driver)
	227	{
	228	int minor_base = class_driver->minor_base;
	229	char name[BUS_ID_SIZE];
	230
	231	#ifdef CONFIG_USB_DYNAMIC_MINORS
	232	minor_base = 0;
	233	#endif
	234
	235	if (intf->minor == -1)
	236	return;
	237
	238	dbg ("removing %d minor", intf->minor);
	239
	240	spin_lock (&minor_lock);
	241	usb_minors[intf->minor] = NULL;
	242	spin_unlock (&minor_lock);
	243
	244	snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
43104f1d	245	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
bd009496	246	intf->usb_dev = NULL;
1da177e4	247	intf->minor = -1;
43104f1d	248	destroy_usb_class();
1da177e4 LT	249	}
	250	EXPORT_SYMBOL(usb_deregister_dev);
	251
	252