[mirror_ubuntu-bionic-kernel.git] / drivers / usb / usb-skeleton.c

/*
 * USB Skeleton driver - 2.2
 *
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License as
 *	published by the Free Software Foundation, version 2.
 *
 * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
 * but has been rewritten to be easier to read and use.
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
#include <linux/mutex.h>


/* Define these values to match your devices */
#define USB_SKEL_VENDOR_ID	0xfff0
#define USB_SKEL_PRODUCT_ID	0xfff0

/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	{ }					/* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, skel_table);

/* to prevent a race between open and disconnect */
static DEFINE_MUTEX(skel_open_lock);


/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE	192

/* our private defines. if this grows any larger, use your own .h file */
#define MAX_TRANSFER		(PAGE_SIZE - 512)
/* MAX_TRANSFER is chosen so that the VM is not stressed by
   allocations > PAGE_SIZE and the number of packets in a page
   is an integer 512 is the largest possible packet on EHCI */
#define WRITES_IN_FLIGHT	8
/* arbitrarily chosen */

/* Structure to hold all of our device specific stuff */
struct usb_skel {
	struct usb_device	*udev;			/* the usb device for this device */
	struct usb_interface	*interface;		/* the interface for this device */
	struct semaphore	limit_sem;		/* limiting the number of writes in progress */
	unsigned char           *bulk_in_buffer;	/* the buffer to receive data */
	size_t			bulk_in_size;		/* the size of the receive buffer */
	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
	struct kref		kref;
	struct mutex		io_mutex;		/* synchronize I/O with disconnect */
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)

static struct usb_driver skel_driver;

static void skel_delete(struct kref *kref)
{
	struct usb_skel *dev = to_skel_dev(kref);

	usb_put_dev(dev->udev);
	kfree(dev->bulk_in_buffer);
	kfree(dev);
}

static int skel_open(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;
	struct usb_interface *interface;
	int subminor;
	int retval = 0;

	subminor = iminor(inode);

	mutex_lock(&skel_open_lock);
	interface = usb_find_interface(&skel_driver, subminor);
	if (!interface) {
		mutex_unlock(&skel_open_lock);
		err ("%s - error, can't find device for minor %d",
		     __FUNCTION__, subminor);
		retval = -ENODEV;
		goto exit;
	}

	dev = usb_get_intfdata(interface);
	if (!dev) {
		mutex_unlock(&skel_open_lock);
		retval = -ENODEV;
		goto exit;
	}

	/* increment our usage count for the device */
	kref_get(&dev->kref);
	/* now we can drop the lock */
	mutex_unlock(&skel_open_lock);

	/* prevent the device from being autosuspended */
	retval = usb_autopm_get_interface(interface);
	if (retval) {
		kref_put(&dev->kref, skel_delete);
		goto exit;
	}

	/* save our object in the file's private structure */
	file->private_data = dev;

exit:
	return retval;
}

static int skel_release(struct inode *inode, struct file *file)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)file->private_data;
	if (dev == NULL)
		return -ENODEV;

	/* allow the device to be autosuspended */
	mutex_lock(&dev->io_mutex);
	if (dev->interface)
		usb_autopm_put_interface(dev->interface);
	mutex_unlock(&dev->io_mutex);

	/* decrement the count on our device */
	kref_put(&dev->kref, skel_delete);
	return 0;
}

static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	int retval;
	int bytes_read;

	dev = (struct usb_skel *)file->private_data;

	mutex_lock(&dev->io_mutex);
	if (!dev->interface) {		/* disconnect() was called */
		retval = -ENODEV;
		goto exit;
	}

	/* do a blocking bulk read to get data from the device */
	retval = usb_bulk_msg(dev->udev,
			      usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
			      dev->bulk_in_buffer,
			      min(dev->bulk_in_size, count),
			      &bytes_read, 10000);

	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
			retval = -EFAULT;
		else
			retval = bytes_read;
	}

exit:
	mutex_unlock(&dev->io_mutex);
	return retval;
}

static void skel_write_bulk_callback(struct urb *urb)
{
	struct usb_skel *dev;

	dev = (struct usb_skel *)urb->context;

	/* sync/async unlink faults aren't errors */
	if (urb->status &&
	    !(urb->status == -ENOENT ||
	      urb->status == -ECONNRESET ||
	      urb->status == -ESHUTDOWN)) {
		err("%s - nonzero write bulk status received: %d",
		    __FUNCTION__, urb->status);
	}

	/* free up our allocated buffer */
	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
			urb->transfer_buffer, urb->transfer_dma);
	up(&dev->limit_sem);
}

static ssize_t skel_write(struct file *file, const char *user_buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	int retval = 0;
	struct urb *urb = NULL;
	char *buf = NULL;
	size_t writesize = min(count, (size_t)MAX_TRANSFER);

	dev = (struct usb_skel *)file->private_data;

	/* verify that we actually have some data to write */
	if (count == 0)
		goto exit;

	/* limit the number of URBs in flight to stop a user from using up all RAM */
	if (down_interruptible(&dev->limit_sem)) {
		retval = -ERESTARTSYS;
		goto exit;
	}

	/* create a urb, and a buffer for it, and copy the data to the urb */
	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!urb) {
		retval = -ENOMEM;
		goto error;
	}

	buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
	if (!buf) {
		retval = -ENOMEM;
		goto error;
	}

	if (copy_from_user(buf, user_buffer, writesize)) {
		retval = -EFAULT;
		goto error;
	}

	/* this lock makes sure we don't submit URBs to gone devices */
	mutex_lock(&dev->io_mutex);
	if (!dev->interface) {		/* disconnect() was called */
		mutex_unlock(&dev->io_mutex);
		retval = -ENODEV;
		goto error;
	}

	/* initialize the urb properly */
	usb_fill_bulk_urb(urb, dev->udev,
			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
			  buf, writesize, skel_write_bulk_callback, dev);
	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	/* send the data out the bulk port */
	retval = usb_submit_urb(urb, GFP_KERNEL);
	mutex_unlock(&dev->io_mutex);
	if (retval) {
		err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
		goto error;
	}

	/* release our reference to this urb, the USB core will eventually free it entirely */
	usb_free_urb(urb);


	return writesize;

error:
	if (urb) {
		usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
		usb_free_urb(urb);
	}
	up(&dev->limit_sem);

exit:
	return retval;
}

static const struct file_operations skel_fops = {
	.owner =	THIS_MODULE,
	.read =		skel_read,
	.write =	skel_write,
	.open =		skel_open,
	.release =	skel_release,
};

/*
 * usb class driver info in order to get a minor number from the usb core,
 * and to have the device registered with the driver core
 */
static struct usb_class_driver skel_class = {
	.name =		"skel%d",
	.fops =		&skel_fops,
	.minor_base =	USB_SKEL_MINOR_BASE,
};

static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id)
{
	struct usb_skel *dev;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	size_t buffer_size;
	int i;
	int retval = -ENOMEM;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		err("Out of memory");
		goto error;
	}
	kref_init(&dev->kref);
	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
	mutex_init(&dev->io_mutex);

	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	/* set up the endpoint information */
	/* use only the first bulk-in and bulk-out endpoints */
	iface_desc = interface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (!dev->bulk_in_endpointAddr &&
		    usb_endpoint_is_bulk_in(endpoint)) {
			/* we found a bulk in endpoint */
			buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
			dev->bulk_in_size = buffer_size;
			dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
			dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
			if (!dev->bulk_in_buffer) {
				err("Could not allocate bulk_in_buffer");
				goto error;
			}
		}

		if (!dev->bulk_out_endpointAddr &&
		    usb_endpoint_is_bulk_out(endpoint)) {
			/* we found a bulk out endpoint */
			dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
		}
	}
	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
		err("Could not find both bulk-in and bulk-out endpoints");
		goto error;
	}

	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* we can register the device now, as it is ready */
	retval = usb_register_dev(interface, &skel_class);
	if (retval) {
		/* something prevented us from registering this driver */
		err("Not able to get a minor for this device.");
		usb_set_intfdata(interface, NULL);
		goto error;
	}

	/* let the user know what node this device is now attached to */
	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	return 0;

error:
	if (dev)
		/* this frees allocated memory */
		kref_put(&dev->kref, skel_delete);
	return retval;
}

static void skel_disconnect(struct usb_interface *interface)
{
	struct usb_skel *dev;
	int minor = interface->minor;

	/* prevent skel_open() from racing skel_disconnect() */
	mutex_lock(&skel_open_lock);

	dev = usb_get_intfdata(interface);
	usb_set_intfdata(interface, NULL);

	/* give back our minor */
	usb_deregister_dev(interface, &skel_class);
	mutex_unlock(&skel_open_lock);

	/* prevent more I/O from starting */
	mutex_lock(&dev->io_mutex);
	dev->interface = NULL;
	mutex_unlock(&dev->io_mutex);


	/* decrement our usage count */
	kref_put(&dev->kref, skel_delete);

	info("USB Skeleton #%d now disconnected", minor);
}

static struct usb_driver skel_driver = {
	.name =		"skeleton",
	.probe =	skel_probe,
	.disconnect =	skel_disconnect,
	.id_table =	skel_table,
	.supports_autosuspend = 1,
};

static int __init usb_skel_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&skel_driver);
	if (result)
		err("usb_register failed. Error number %d", result);

	return result;
}

static void __exit usb_skel_exit(void)
{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&skel_driver);
}

module_init(usb_skel_init);
module_exit(usb_skel_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4	1	/*
c0704541	2	* USB Skeleton driver - 2.2
1da177e4 LT	3	*
	4	* Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation, version 2.
	9	*
c0704541	10	* This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
121e287c	11	* but has been rewritten to be easier to read and use.
1da177e4 LT	12	*
	13	*/
	14
1da177e4 LT	15	#include <linux/kernel.h>
	16	#include <linux/errno.h>
	17	#include <linux/init.h>
	18	#include <linux/slab.h>
	19	#include <linux/module.h>
	20	#include <linux/kref.h>
	21	#include <asm/uaccess.h>
	22	#include <linux/usb.h>
121e287c	23	#include <linux/mutex.h>
1da177e4 LT	24
	25
	26	/* Define these values to match your devices */
	27	#define USB_SKEL_VENDOR_ID 0xfff0
	28	#define USB_SKEL_PRODUCT_ID 0xfff0
	29
	30	/* table of devices that work with this driver */
	31	static struct usb_device_id skel_table [] = {
	32	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
	33	{ } /* Terminating entry */
	34	};
c0704541	35	MODULE_DEVICE_TABLE(usb, skel_table);
1da177e4	36
5d9b89b3 ON	37	/* to prevent a race between open and disconnect */
	38	static DEFINE_MUTEX(skel_open_lock);
	39
1da177e4 LT	40
	41	/* Get a minor range for your devices from the usb maintainer */
	42	#define USB_SKEL_MINOR_BASE 192
	43
ff906518	44	/* our private defines. if this grows any larger, use your own .h file */
c0704541	45	#define MAX_TRANSFER (PAGE_SIZE - 512)
ba35e02b ON	46	/* MAX_TRANSFER is chosen so that the VM is not stressed by
	47	allocations > PAGE_SIZE and the number of packets in a page
	48	is an integer 512 is the largest possible packet on EHCI */
ff906518	49	#define WRITES_IN_FLIGHT 8
ba35e02b	50	/* arbitrarily chosen */
ff906518	51
1da177e4 LT	52	/* Structure to hold all of our device specific stuff */
1da177e4 LT	53	struct usb_skel {
ba35e02b ON	54	struct usb_device udev; / the usb device for this device */
ba35e02b ON	55	struct usb_interface interface; / the interface for this device */
ff906518	56	struct semaphore limit_sem; /* limiting the number of writes in progress */
c0704541	57	unsigned char bulk_in_buffer; / the buffer to receive data */
1da177e4 LT	58	size_t bulk_in_size; /* the size of the receive buffer */
	59	__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
	60	__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
	61	struct kref kref;
121e287c	62	struct mutex io_mutex; /* synchronize I/O with disconnect */
1da177e4 LT	63	};
	64	#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
	65
	66	static struct usb_driver skel_driver;
	67
	68	static void skel_delete(struct kref *kref)
c0704541	69	{
1da177e4 LT	70	struct usb_skel *dev = to_skel_dev(kref);
	71
	72	usb_put_dev(dev->udev);
c0704541 LFC	73	kfree(dev->bulk_in_buffer);
c0704541 LFC	74	kfree(dev);
1da177e4 LT	75	}
	76
	77	static int skel_open(struct inode inode, struct file file)
	78	{
	79	struct usb_skel *dev;
	80	struct usb_interface *interface;
	81	int subminor;
	82	int retval = 0;
	83
	84	subminor = iminor(inode);
	85
5d9b89b3	86	mutex_lock(&skel_open_lock);
1da177e4 LT	87	interface = usb_find_interface(&skel_driver, subminor);
1da177e4 LT	88	if (!interface) {
5d9b89b3	89	mutex_unlock(&skel_open_lock);
1da177e4 LT	90	err ("%s - error, can't find device for minor %d",
	91	__FUNCTION__, subminor);
	92	retval = -ENODEV;
	93	goto exit;
	94	}
	95
	96	dev = usb_get_intfdata(interface);
	97	if (!dev) {
5d9b89b3	98	mutex_unlock(&skel_open_lock);
1da177e4 LT	99	retval = -ENODEV;
	100	goto exit;
	101	}
	102
5b064708 ON	103	/* increment our usage count for the device */
5b064708 ON	104	kref_get(&dev->kref);
5d9b89b3 ON	105	/* now we can drop the lock */
5d9b89b3 ON	106	mutex_unlock(&skel_open_lock);
5b064708	107
01d883d4 AS	108	/* prevent the device from being autosuspended */
01d883d4 AS	109	retval = usb_autopm_get_interface(interface);
5b064708 ON	110	if (retval) {
5b064708 ON	111	kref_put(&dev->kref, skel_delete);
01d883d4	112	goto exit;
5b064708	113	}
1da177e4 LT	114
	115	/* save our object in the file's private structure */
	116	file->private_data = dev;
	117
	118	exit:
	119	return retval;
	120	}
	121
	122	static int skel_release(struct inode inode, struct file file)
	123	{
	124	struct usb_skel *dev;
	125
	126	dev = (struct usb_skel *)file->private_data;
	127	if (dev == NULL)
	128	return -ENODEV;
	129
01d883d4 AS	130	/* allow the device to be autosuspended */
	131	mutex_lock(&dev->io_mutex);
	132	if (dev->interface)
	133	usb_autopm_put_interface(dev->interface);
	134	mutex_unlock(&dev->io_mutex);
	135
1da177e4 LT	136	/* decrement the count on our device */
	137	kref_put(&dev->kref, skel_delete);
	138	return 0;
	139	}
	140
	141	static ssize_t skel_read(struct file file, char buffer, size_t count, loff_t *ppos)
	142	{
	143	struct usb_skel *dev;
c0704541	144	int retval;
1da177e4 LT	145	int bytes_read;
	146
	147	dev = (struct usb_skel *)file->private_data;
121e287c AS	148
	149	mutex_lock(&dev->io_mutex);
	150	if (!dev->interface) { /* disconnect() was called */
	151	retval = -ENODEV;
	152	goto exit;
	153	}
	154
1da177e4 LT	155	/* do a blocking bulk read to get data from the device */
	156	retval = usb_bulk_msg(dev->udev,
	157	usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
	158	dev->bulk_in_buffer,
	159	min(dev->bulk_in_size, count),
	160	&bytes_read, 10000);
	161
	162	/* if the read was successful, copy the data to userspace */
	163	if (!retval) {
	164	if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
	165	retval = -EFAULT;
	166	else
	167	retval = bytes_read;
	168	}
	169
121e287c AS	170	exit:
121e287c AS	171	mutex_unlock(&dev->io_mutex);
1da177e4 LT	172	return retval;
	173	}
	174
7d12e780	175	static void skel_write_bulk_callback(struct urb *urb)
1da177e4 LT	176	{
	177	struct usb_skel *dev;
	178
	179	dev = (struct usb_skel *)urb->context;
	180
	181	/* sync/async unlink faults aren't errors */
c0704541 LFC	182	if (urb->status &&
c0704541 LFC	183	!(urb->status == -ENOENT \|\|
1da177e4 LT	184	urb->status == -ECONNRESET \|\|
1da177e4 LT	185	urb->status == -ESHUTDOWN)) {
c0704541	186	err("%s - nonzero write bulk status received: %d",
1da177e4 LT	187	__FUNCTION__, urb->status);
	188	}
	189
	190	/* free up our allocated buffer */
c0704541	191	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
1da177e4	192	urb->transfer_buffer, urb->transfer_dma);
ff906518	193	up(&dev->limit_sem);
1da177e4 LT	194	}
	195
	196	static ssize_t skel_write(struct file file, const char user_buffer, size_t count, loff_t *ppos)
	197	{
	198	struct usb_skel *dev;
	199	int retval = 0;
	200	struct urb *urb = NULL;
	201	char *buf = NULL;
c8dd7709	202	size_t writesize = min(count, (size_t)MAX_TRANSFER);
1da177e4 LT	203
	204	dev = (struct usb_skel *)file->private_data;
	205
	206	/* verify that we actually have some data to write */
	207	if (count == 0)
	208	goto exit;
	209
ff906518	210	/* limit the number of URBs in flight to stop a user from using up all RAM */
c8dd7709 SB	211	if (down_interruptible(&dev->limit_sem)) {
	212	retval = -ERESTARTSYS;
	213	goto exit;
	214	}
ff906518	215
1da177e4 LT	216	/* create a urb, and a buffer for it, and copy the data to the urb */
	217	urb = usb_alloc_urb(0, GFP_KERNEL);
	218	if (!urb) {
	219	retval = -ENOMEM;
	220	goto error;
	221	}
	222
ff906518	223	buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
1da177e4 LT	224	if (!buf) {
	225	retval = -ENOMEM;
	226	goto error;
	227	}
	228
ff906518	229	if (copy_from_user(buf, user_buffer, writesize)) {
1da177e4 LT	230	retval = -EFAULT;
	231	goto error;
	232	}
	233
ba35e02b ON	234	/* this lock makes sure we don't submit URBs to gone devices */
	235	mutex_lock(&dev->io_mutex);
	236	if (!dev->interface) { /* disconnect() was called */
	237	mutex_unlock(&dev->io_mutex);
	238	retval = -ENODEV;
	239	goto error;
	240	}
	241
1da177e4 LT	242	/* initialize the urb properly */
	243	usb_fill_bulk_urb(urb, dev->udev,
	244	usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
ff906518	245	buf, writesize, skel_write_bulk_callback, dev);
1da177e4 LT	246	urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;
	247
	248	/* send the data out the bulk port */
	249	retval = usb_submit_urb(urb, GFP_KERNEL);
ba35e02b	250	mutex_unlock(&dev->io_mutex);
1da177e4 LT	251	if (retval) {
	252	err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
	253	goto error;
	254	}
	255
	256	/* release our reference to this urb, the USB core will eventually free it entirely */
	257	usb_free_urb(urb);
	258
ba35e02b	259
ff906518	260	return writesize;
1da177e4 LT	261
1da177e4 LT	262	error:
121e287c AS	263	if (urb) {
	264	usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
	265	usb_free_urb(urb);
	266	}
ff906518	267	up(&dev->limit_sem);
121e287c AS	268
121e287c AS	269	exit:
1da177e4 LT	270	return retval;
	271	}
	272
066202dd	273	static const struct file_operations skel_fops = {
1da177e4 LT	274	.owner = THIS_MODULE,
	275	.read = skel_read,
	276	.write = skel_write,
	277	.open = skel_open,
	278	.release = skel_release,
	279	};
	280
c0704541	281	/*
1da177e4	282	* usb class driver info in order to get a minor number from the usb core,
595b14cb	283	* and to have the device registered with the driver core
1da177e4 LT	284	*/
1da177e4 LT	285	static struct usb_class_driver skel_class = {
d6e5bcf4	286	.name = "skel%d",
1da177e4	287	.fops = &skel_fops,
1da177e4 LT	288	.minor_base = USB_SKEL_MINOR_BASE,
	289	};
	290
	291	static int skel_probe(struct usb_interface interface, const struct usb_device_id id)
	292	{
c0704541	293	struct usb_skel *dev;
1da177e4 LT	294	struct usb_host_interface *iface_desc;
	295	struct usb_endpoint_descriptor *endpoint;
	296	size_t buffer_size;
	297	int i;
	298	int retval = -ENOMEM;
	299
	300	/* allocate memory for our device state and initialize it */
ff906518	301	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
c0704541	302	if (!dev) {
1da177e4 LT	303	err("Out of memory");
	304	goto error;
	305	}
1da177e4	306	kref_init(&dev->kref);
ff906518	307	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
121e287c	308	mutex_init(&dev->io_mutex);
1da177e4 LT	309
	310	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	311	dev->interface = interface;
	312
	313	/* set up the endpoint information */
	314	/* use only the first bulk-in and bulk-out endpoints */
	315	iface_desc = interface->cur_altsetting;
	316	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
	317	endpoint = &iface_desc->endpoint[i].desc;
	318
	319	if (!dev->bulk_in_endpointAddr &&
c0704541	320	usb_endpoint_is_bulk_in(endpoint)) {
1da177e4 LT	321	/* we found a bulk in endpoint */
	322	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
	323	dev->bulk_in_size = buffer_size;
	324	dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
	325	dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
	326	if (!dev->bulk_in_buffer) {
	327	err("Could not allocate bulk_in_buffer");
	328	goto error;
	329	}
	330	}
	331
	332	if (!dev->bulk_out_endpointAddr &&
c0704541	333	usb_endpoint_is_bulk_out(endpoint)) {
1da177e4 LT	334	/* we found a bulk out endpoint */
	335	dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
	336	}
	337	}
	338	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
	339	err("Could not find both bulk-in and bulk-out endpoints");
	340	goto error;
	341	}
	342
	343	/* save our data pointer in this interface device */
	344	usb_set_intfdata(interface, dev);
	345
	346	/* we can register the device now, as it is ready */
	347	retval = usb_register_dev(interface, &skel_class);
	348	if (retval) {
	349	/* something prevented us from registering this driver */
	350	err("Not able to get a minor for this device.");
	351	usb_set_intfdata(interface, NULL);
	352	goto error;
	353	}
	354
	355	/* let the user know what node this device is now attached to */
	356	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	357	return 0;
	358
	359	error:
	360	if (dev)
ba35e02b	361	/* this frees allocated memory */
1da177e4 LT	362	kref_put(&dev->kref, skel_delete);
	363	return retval;
	364	}
	365
	366	static void skel_disconnect(struct usb_interface *interface)
	367	{
	368	struct usb_skel *dev;
	369	int minor = interface->minor;
	370
	371	/* prevent skel_open() from racing skel_disconnect() */
5d9b89b3	372	mutex_lock(&skel_open_lock);
1da177e4 LT	373
	374	dev = usb_get_intfdata(interface);
	375	usb_set_intfdata(interface, NULL);
	376
	377	/* give back our minor */
	378	usb_deregister_dev(interface, &skel_class);
5d9b89b3	379	mutex_unlock(&skel_open_lock);
1da177e4	380
121e287c AS	381	/* prevent more I/O from starting */
	382	mutex_lock(&dev->io_mutex);
	383	dev->interface = NULL;
	384	mutex_unlock(&dev->io_mutex);
	385
ba35e02b	386
1da177e4 LT	387
	388	/* decrement our usage count */
	389	kref_put(&dev->kref, skel_delete);
	390
	391	info("USB Skeleton #%d now disconnected", minor);
	392	}
	393
	394	static struct usb_driver skel_driver = {
1da177e4 LT	395	.name = "skeleton",
	396	.probe = skel_probe,
	397	.disconnect = skel_disconnect,
	398	.id_table = skel_table,
ba35e02b	399	.supports_autosuspend = 1,
1da177e4 LT	400	};
	401
	402	static int __init usb_skel_init(void)
	403	{
	404	int result;
	405
	406	/* register this driver with the USB subsystem */
	407	result = usb_register(&skel_driver);
	408	if (result)
	409	err("usb_register failed. Error number %d", result);
	410
	411	return result;
	412	}
	413
	414	static void __exit usb_skel_exit(void)
	415	{
	416	/* deregister this driver with the USB subsystem */
	417	usb_deregister(&skel_driver);
	418	}
	419
c0704541 LFC	420	module_init(usb_skel_init);
c0704541 LFC	421	module_exit(usb_skel_exit);
1da177e4 LT	422
1da177e4 LT	423	MODULE_LICENSE("GPL");