[linux-block.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/errno.h>
#include <linux/rwsem.h>
#include <linux/smp_lock.h>
#include <linux/usb.h>

#include "usb.h"

#define MAX_USB_MINORS	256
static const struct file_operations *usb_minors[MAX_USB_MINORS];
static DECLARE_RWSEM(minor_rwsem);

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;

	lock_kernel();
	down_read(&minor_rwsem);
	c = usb_minors[minor];

	if (!c || !(new_fops = fops_get(c)))
		goto done;

	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);
 done:
	up_read(&minor_rwsem);
	unlock_kernel();
	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;

	down_write(&minor_rwsem);
	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
		if (usb_minors[minor])
			continue;

		usb_minors[minor] = class_driver->fops;

		retval = 0;
		break;
	}
	up_write(&minor_rwsem);

	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)) {
		down_write(&minor_rwsem);
		usb_minors[intf->minor] = NULL;
		up_write(&minor_rwsem);
		retval = PTR_ERR(intf->usb_dev);
	}
exit:
	return retval;
}
EXPORT_SYMBOL_GPL(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);

	down_write(&minor_rwsem);
	usb_minors[intf->minor] = NULL;
	up_write(&minor_rwsem);

	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_GPL(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	19	#include <linux/errno.h>
d4ead16f	20	#include <linux/rwsem.h>
20613f24	21	#include <linux/smp_lock.h>
1da177e4 LT	22	#include <linux/usb.h>
1da177e4 LT	23
6d5e8254 GK	24	#include "usb.h"
6d5e8254 GK	25
1da177e4	26	#define MAX_USB_MINORS 256
99ac48f5	27	static const struct file_operations *usb_minors[MAX_USB_MINORS];
d4ead16f	28	static DECLARE_RWSEM(minor_rwsem);
1da177e4 LT	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	36
20613f24	37	lock_kernel();
d4ead16f	38	down_read(&minor_rwsem);
1da177e4 LT	39	c = usb_minors[minor];
1da177e4 LT	40
d4ead16f AS	41	if (!c \|\| !(new_fops = fops_get(c)))
d4ead16f AS	42	goto done;
1da177e4 LT	43
	44	old_fops = file->f_op;
	45	file->f_op = new_fops;
	46	/* Curiouser and curiouser... NULL ->open() as "no device" ? */
	47	if (file->f_op->open)
	48	err = file->f_op->open(inode,file);
	49	if (err) {
	50	fops_put(file->f_op);
	51	file->f_op = fops_get(old_fops);
	52	}
	53	fops_put(old_fops);
d4ead16f AS	54	done:
d4ead16f AS	55	up_read(&minor_rwsem);
20613f24	56	unlock_kernel();
1da177e4 LT	57	return err;
	58	}
	59
066202dd	60	static const struct file_operations usb_fops = {
1da177e4 LT	61	.owner = THIS_MODULE,
	62	.open = usb_open,
	63	};
	64
43104f1d GKH	65	static struct usb_class {
	66	struct kref kref;
	67	struct class *class;
	68	} *usb_class;
1da177e4	69
43104f1d	70	static int init_usb_class(void)
1da177e4	71	{
43104f1d	72	int result = 0;
1da177e4	73
43104f1d GKH	74	if (usb_class != NULL) {
	75	kref_get(&usb_class->kref);
	76	goto exit;
	77	}
	78
	79	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
	80	if (!usb_class) {
	81	result = -ENOMEM;
	82	goto exit;
1da177e4 LT	83	}
1da177e4 LT	84
43104f1d GKH	85	kref_init(&usb_class->kref);
	86	usb_class->class = class_create(THIS_MODULE, "usb");
	87	if (IS_ERR(usb_class->class)) {
	88	result = IS_ERR(usb_class->class);
56b22935	89	err("class_create failed for usb devices");
43104f1d GKH	90	kfree(usb_class);
43104f1d GKH	91	usb_class = NULL;
1da177e4 LT	92	}
1da177e4 LT	93
43104f1d GKH	94	exit:
	95	return result;
	96	}
	97
	98	static void release_usb_class(struct kref *kref)
	99	{
	100	/* Ok, we cheat as we know we only have one usb_class */
	101	class_destroy(usb_class->class);
	102	kfree(usb_class);
	103	usb_class = NULL;
	104	}
	105
	106	static void destroy_usb_class(void)
	107	{
	108	if (usb_class)
	109	kref_put(&usb_class->kref, release_usb_class);
	110	}
	111
	112	int usb_major_init(void)
	113	{
	114	int error;
	115
	116	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
	117	if (error)
	118	err("unable to get major %d for usb devices", USB_MAJOR);
	119
1da177e4 LT	120	return error;
	121	}
	122
	123	void usb_major_cleanup(void)
	124	{
1da177e4 LT	125	unregister_chrdev(USB_MAJOR, "usb");
	126	}
	127
	128	/**
	129	* usb_register_dev - register a USB device, and ask for a minor number
	130	* @intf: pointer to the usb_interface that is being registered
	131	* @class_driver: pointer to the usb_class_driver for this device
	132	*
	133	* This should be called by all USB drivers that use the USB major number.
	134	* If CONFIG_USB_DYNAMIC_MINORS is enabled, the minor number will be
	135	* dynamically allocated out of the list of available ones. If it is not
	136	* enabled, the minor number will be based on the next available free minor,
	137	* starting at the class_driver->minor_base.
	138	*
d6e5bcf4	139	* This function also creates a usb class device in the sysfs tree.
1da177e4 LT	140	*
	141	* usb_deregister_dev() must be called when the driver is done with
	142	* the minor numbers given out by this function.
	143	*
	144	* Returns -EINVAL if something bad happens with trying to register a
	145	* device, and 0 on success.
	146	*/
	147	int usb_register_dev(struct usb_interface *intf,
	148	struct usb_class_driver *class_driver)
	149	{
	150	int retval = -EINVAL;
	151	int minor_base = class_driver->minor_base;
	152	int minor = 0;
	153	char name[BUS_ID_SIZE];
	154	char *temp;
	155
	156	#ifdef CONFIG_USB_DYNAMIC_MINORS
	157	/*
	158	* We don't care what the device tries to start at, we want to start
	159	* at zero to pack the devices into the smallest available space with
	160	* no holes in the minor range.
	161	*/
	162	minor_base = 0;
	163	#endif
	164	intf->minor = -1;
	165
	166	dbg ("looking for a minor, starting at %d", minor_base);
	167
	168	if (class_driver->fops == NULL)
	169	goto exit;
	170
d4ead16f	171	down_write(&minor_rwsem);
1da177e4 LT	172	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
	173	if (usb_minors[minor])
	174	continue;
	175
	176	usb_minors[minor] = class_driver->fops;
	177
	178	retval = 0;
	179	break;
	180	}
d4ead16f	181	up_write(&minor_rwsem);
1da177e4	182
43104f1d GKH	183	if (retval)
	184	goto exit;
	185
	186	retval = init_usb_class();
1da177e4 LT	187	if (retval)
	188	goto exit;
	189
	190	intf->minor = minor;
	191
1da177e4	192	/* create a usb class device for this usb interface */
d6e5bcf4	193	snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
1da177e4 LT	194	temp = strrchr(name, '/');
	195	if (temp && (temp[1] != 0x00))
	196	++temp;
	197	else
	198	temp = name;
0873c764 GKH	199	intf->usb_dev = device_create(usb_class->class, &intf->dev,
	200	MKDEV(USB_MAJOR, minor), "%s", temp);
	201	if (IS_ERR(intf->usb_dev)) {
d4ead16f	202	down_write(&minor_rwsem);
1da177e4	203	usb_minors[intf->minor] = NULL;
d4ead16f	204	up_write(&minor_rwsem);
0873c764	205	retval = PTR_ERR(intf->usb_dev);
1da177e4 LT	206	}
	207	exit:
	208	return retval;
	209	}
782e70c6	210	EXPORT_SYMBOL_GPL(usb_register_dev);
1da177e4 LT	211
	212	/**
	213	* usb_deregister_dev - deregister a USB device's dynamic minor.
	214	* @intf: pointer to the usb_interface that is being deregistered
	215	* @class_driver: pointer to the usb_class_driver for this device
	216	*
	217	* Used in conjunction with usb_register_dev(). This function is called
	218	* when the USB driver is finished with the minor numbers gotten from a
	219	* call to usb_register_dev() (usually when the device is disconnected
	220	* from the system.)
	221	*
d6e5bcf4 GKH	222	* This function also removes the usb class device from the sysfs tree.
d6e5bcf4 GKH	223	*
1da177e4 LT	224	* This should be called by all drivers that use the USB major number.
	225	*/
	226	void usb_deregister_dev(struct usb_interface *intf,
	227	struct usb_class_driver *class_driver)
	228	{
	229	int minor_base = class_driver->minor_base;
	230	char name[BUS_ID_SIZE];
	231
	232	#ifdef CONFIG_USB_DYNAMIC_MINORS
	233	minor_base = 0;
	234	#endif
	235
	236	if (intf->minor == -1)
	237	return;
	238
	239	dbg ("removing %d minor", intf->minor);
	240
d4ead16f	241	down_write(&minor_rwsem);
1da177e4	242	usb_minors[intf->minor] = NULL;
d4ead16f	243	up_write(&minor_rwsem);
1da177e4 LT	244
1da177e4 LT	245	snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
0873c764 GKH	246	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
0873c764 GKH	247	intf->usb_dev = NULL;
1da177e4	248	intf->minor = -1;
43104f1d	249	destroy_usb_class();
1da177e4	250	}
782e70c6	251	EXPORT_SYMBOL_GPL(usb_deregister_dev);