[deliverable/linux.git] / drivers / usb / core / file.c

/*
 * drivers/usb/core/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/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 const 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->class_dev = class_device_create(usb_class->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->class, MKDEV(USB_MAJOR, intf->minor));
	intf->class_dev = NULL;
	intf->minor = -1;
	destroy_usb_class();
}
EXPORT_SYMBOL(usb_deregister_dev);
Commit	Line	Data
1da177e4	1	/*
f30c2269	2	* drivers/usb/core/file.c
1da177e4 LT	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
1da177e4	18	#include <linux/module.h>
1da177e4 LT	19	#include <linux/spinlock.h>
1da177e4 LT	20	#include <linux/errno.h>
1da177e4 LT	21	#include <linux/usb.h>
1da177e4 LT	22
6d5e8254 GK	23	#include "usb.h"
6d5e8254 GK	24
1da177e4	25	#define MAX_USB_MINORS 256
99ac48f5	26	static const struct file_operations *usb_minors[MAX_USB_MINORS];
1da177e4 LT	27	static DEFINE_SPINLOCK(minor_lock);
	28
	29	static int usb_open(struct inode * inode, struct file * file)
	30	{
	31	int minor = iminor(inode);
99ac48f5	32	const struct file_operations *c;
1da177e4	33	int err = -ENODEV;
99ac48f5	34	const struct file_operations old_fops, new_fops = NULL;
1da177e4 LT	35
	36	spin_lock (&minor_lock);
	37	c = usb_minors[minor];
	38
	39	if (!c \|\| !(new_fops = fops_get(c))) {
	40	spin_unlock(&minor_lock);
	41	return err;
	42	}
	43	spin_unlock(&minor_lock);
	44
	45	old_fops = file->f_op;
	46	file->f_op = new_fops;
	47	/* Curiouser and curiouser... NULL ->open() as "no device" ? */
	48	if (file->f_op->open)
	49	err = file->f_op->open(inode,file);
	50	if (err) {
	51	fops_put(file->f_op);
	52	file->f_op = fops_get(old_fops);
	53	}
	54	fops_put(old_fops);
	55	return err;
	56	}
	57
066202dd	58	static const struct file_operations usb_fops = {
1da177e4 LT	59	.owner = THIS_MODULE,
	60	.open = usb_open,
	61	};
	62
43104f1d GKH	63	static struct usb_class {
	64	struct kref kref;
	65	struct class *class;
	66	} *usb_class;
1da177e4	67
43104f1d	68	static int init_usb_class(void)
1da177e4	69	{
43104f1d	70	int result = 0;
1da177e4	71
43104f1d GKH	72	if (usb_class != NULL) {
	73	kref_get(&usb_class->kref);
	74	goto exit;
	75	}
	76
	77	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
	78	if (!usb_class) {
	79	result = -ENOMEM;
	80	goto exit;
1da177e4 LT	81	}
1da177e4 LT	82
43104f1d GKH	83	kref_init(&usb_class->kref);
	84	usb_class->class = class_create(THIS_MODULE, "usb");
	85	if (IS_ERR(usb_class->class)) {
	86	result = IS_ERR(usb_class->class);
56b22935	87	err("class_create failed for usb devices");
43104f1d GKH	88	kfree(usb_class);
43104f1d GKH	89	usb_class = NULL;
1da177e4 LT	90	}
1da177e4 LT	91
43104f1d GKH	92	exit:
	93	return result;
	94	}
	95
	96	static void release_usb_class(struct kref *kref)
	97	{
	98	/* Ok, we cheat as we know we only have one usb_class */
	99	class_destroy(usb_class->class);
	100	kfree(usb_class);
	101	usb_class = NULL;
	102	}
	103
	104	static void destroy_usb_class(void)
	105	{
	106	if (usb_class)
	107	kref_put(&usb_class->kref, release_usb_class);
	108	}
	109
	110	int usb_major_init(void)
	111	{
	112	int error;
	113
	114	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
	115	if (error)
	116	err("unable to get major %d for usb devices", USB_MAJOR);
	117
1da177e4 LT	118	return error;
	119	}
	120
	121	void usb_major_cleanup(void)
	122	{
1da177e4 LT	123	unregister_chrdev(USB_MAJOR, "usb");
	124	}
	125
	126	/**
	127	* usb_register_dev - register a USB device, and ask for a minor number
	128	* @intf: pointer to the usb_interface that is being registered
	129	* @class_driver: pointer to the usb_class_driver for this device
	130	*
	131	* This should be called by all USB drivers that use the USB major number.
	132	* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
	133	* dynamically allocated out of the list of available ones. If it is not
	134	* enabled, the minor number will be based on the next available free minor,
	135	* starting at the class_driver->minor_base.
	136	*
d6e5bcf4	137	* This function also creates a usb class device in the sysfs tree.
1da177e4 LT	138	*
	139	* usb_deregister_dev() must be called when the driver is done with
	140	* the minor numbers given out by this function.
	141	*
	142	* Returns -EINVAL if something bad happens with trying to register a
	143	* device, and 0 on success.
	144	*/
	145	int usb_register_dev(struct usb_interface *intf,
	146	struct usb_class_driver *class_driver)
	147	{
	148	int retval = -EINVAL;
	149	int minor_base = class_driver->minor_base;
	150	int minor = 0;
	151	char name[BUS_ID_SIZE];
	152	char *temp;
	153
	154	#ifdef CONFIG_USB_DYNAMIC_MINORS
	155	/*
	156	* We don't care what the device tries to start at, we want to start
	157	* at zero to pack the devices into the smallest available space with
	158	* no holes in the minor range.
	159	*/
	160	minor_base = 0;
	161	#endif
	162	intf->minor = -1;
	163
	164	dbg ("looking for a minor, starting at %d", minor_base);
	165
	166	if (class_driver->fops == NULL)
	167	goto exit;
	168
	169	spin_lock (&minor_lock);
	170	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
	171	if (usb_minors[minor])
	172	continue;
	173
	174	usb_minors[minor] = class_driver->fops;
	175
	176	retval = 0;
	177	break;
	178	}
	179	spin_unlock (&minor_lock);
	180
43104f1d GKH	181	if (retval)
	182	goto exit;
	183
	184	retval = init_usb_class();
1da177e4 LT	185	if (retval)
	186	goto exit;
	187
	188	intf->minor = minor;
	189
1da177e4	190	/* create a usb class device for this usb interface */
d6e5bcf4	191	snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
1da177e4 LT	192	temp = strrchr(name, '/');
	193	if (temp && (temp[1] != 0x00))
	194	++temp;
	195	else
	196	temp = name;
27fb4f0a GKH	197	intf->class_dev = class_device_create(usb_class->class, NULL,
	198	MKDEV(USB_MAJOR, minor),
	199	&intf->dev, "%s", temp);
	200	if (IS_ERR(intf->class_dev)) {
1da177e4 LT	201	spin_lock (&minor_lock);
	202	usb_minors[intf->minor] = NULL;
	203	spin_unlock (&minor_lock);
27fb4f0a	204	retval = PTR_ERR(intf->class_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);
27fb4f0a GKH	245	class_device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
27fb4f0a GKH	246	intf->class_dev = NULL;
1da177e4	247	intf->minor = -1;
43104f1d	248	destroy_usb_class();
1da177e4 LT	249	}
	250	EXPORT_SYMBOL(usb_deregister_dev);
	251
	252