[GitHub/LineageOS/android_kernel_motorola_exynos9610.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);


/* 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 */
	struct usb_anchor	submitted;		/* in case we need to retract our submissions */
	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 */
	int			errors;			/* the last request tanked */
	spinlock_t		err_lock;		/* lock for errors */
	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_draw_down(struct usb_skel *dev);

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);

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

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

	/* increment our usage count for the device */
	kref_get(&dev->kref);

	/* 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 int skel_flush(struct file *file, fl_owner_t id)
{
	struct usb_skel *dev;
	int res;

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

	/* wait for io to stop */
	mutex_lock(&dev->io_mutex);
	skel_draw_down(dev);

	/* read out errors, leave subsequent opens a clean slate */
	spin_lock_irq(&dev->err_lock);
	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
	dev->errors = 0;
	spin_unlock_irq(&dev->err_lock);

	mutex_unlock(&dev->io_mutex);

	return res;
}

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) {
		if(!(urb->status == -ENOENT ||
		    urb->status == -ECONNRESET ||
		    urb->status == -ESHUTDOWN))
			err("%s - nonzero write bulk status received: %d",
			    __FUNCTION__, urb->status);

		spin_lock(&dev->err_lock);
		dev->errors = urb->status;
		spin_unlock(&dev->err_lock);
	}

	/* 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;
	}

	spin_lock_irq(&dev->err_lock);
	if ((retval = dev->errors) < 0) {
		/* any error is reported once */
		dev->errors = 0;
		/* to preserve notifications about reset */
		retval = (retval == -EPIPE) ? retval : -EIO;
	}
	spin_unlock_irq(&dev->err_lock);
	if (retval < 0)
		goto error;

	/* 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;
	usb_anchor_urb(urb, &dev->submitted);

	/* 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_unanchor;
	}

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


	return writesize;

error_unanchor:
	usb_unanchor_urb(urb);
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,
	.flush =	skel_flush,
};

/*
 * 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);
	spin_lock_init(&dev->err_lock);
	init_usb_anchor(&dev->submitted);

	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;

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

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

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

	usb_kill_anchored_urbs(&dev->submitted);

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

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

static void skel_draw_down(struct usb_skel *dev)
{
	int time;

	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
	if (!time)
		usb_kill_anchored_urbs(&dev->submitted);
}

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 LT	36
	37
	38	/* Get a minor range for your devices from the usb maintainer */
	39	#define USB_SKEL_MINOR_BASE 192
	40
ff906518	41	/* our private defines. if this grows any larger, use your own .h file */
c0704541	42	#define MAX_TRANSFER (PAGE_SIZE - 512)
ba35e02b ON	43	/* MAX_TRANSFER is chosen so that the VM is not stressed by
	44	allocations > PAGE_SIZE and the number of packets in a page
	45	is an integer 512 is the largest possible packet on EHCI */
ff906518	46	#define WRITES_IN_FLIGHT 8
ba35e02b	47	/* arbitrarily chosen */
ff906518	48
1da177e4 LT	49	/* Structure to hold all of our device specific stuff */
1da177e4 LT	50	struct usb_skel {
ba35e02b ON	51	struct usb_device udev; / the usb device for this device */
ba35e02b ON	52	struct usb_interface interface; / the interface for this device */
ff906518	53	struct semaphore limit_sem; /* limiting the number of writes in progress */
403dfb58	54	struct usb_anchor submitted; /* in case we need to retract our submissions */
c0704541	55	unsigned char bulk_in_buffer; / the buffer to receive data */
1da177e4 LT	56	size_t bulk_in_size; /* the size of the receive buffer */
	57	__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
	58	__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
403dfb58 ON	59	int errors; /* the last request tanked */
403dfb58 ON	60	spinlock_t err_lock; /* lock for errors */
1da177e4	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;
403dfb58	67	static void skel_draw_down(struct usb_skel *dev);
1da177e4 LT	68
1da177e4 LT	69	static void skel_delete(struct kref *kref)
c0704541	70	{
1da177e4 LT	71	struct usb_skel *dev = to_skel_dev(kref);
	72
	73	usb_put_dev(dev->udev);
c0704541 LFC	74	kfree(dev->bulk_in_buffer);
c0704541 LFC	75	kfree(dev);
1da177e4 LT	76	}
	77
	78	static int skel_open(struct inode inode, struct file file)
	79	{
	80	struct usb_skel *dev;
	81	struct usb_interface *interface;
	82	int subminor;
	83	int retval = 0;
	84
	85	subminor = iminor(inode);
	86
	87	interface = usb_find_interface(&skel_driver, subminor);
	88	if (!interface) {
	89	err ("%s - error, can't find device for minor %d",
	90	__FUNCTION__, subminor);
	91	retval = -ENODEV;
	92	goto exit;
	93	}
	94
	95	dev = usb_get_intfdata(interface);
	96	if (!dev) {
	97	retval = -ENODEV;
	98	goto exit;
	99	}
	100
5b064708 ON	101	/* increment our usage count for the device */
	102	kref_get(&dev->kref);
	103
01d883d4 AS	104	/* prevent the device from being autosuspended */
01d883d4 AS	105	retval = usb_autopm_get_interface(interface);
5b064708 ON	106	if (retval) {
5b064708 ON	107	kref_put(&dev->kref, skel_delete);
01d883d4	108	goto exit;
5b064708	109	}
1da177e4 LT	110
	111	/* save our object in the file's private structure */
	112	file->private_data = dev;
	113
	114	exit:
	115	return retval;
	116	}
	117
	118	static int skel_release(struct inode inode, struct file file)
	119	{
	120	struct usb_skel *dev;
	121
	122	dev = (struct usb_skel *)file->private_data;
	123	if (dev == NULL)
	124	return -ENODEV;
	125
01d883d4 AS	126	/* allow the device to be autosuspended */
	127	mutex_lock(&dev->io_mutex);
	128	if (dev->interface)
	129	usb_autopm_put_interface(dev->interface);
	130	mutex_unlock(&dev->io_mutex);
	131
1da177e4 LT	132	/* decrement the count on our device */
	133	kref_put(&dev->kref, skel_delete);
	134	return 0;
	135	}
	136
403dfb58 ON	137	static int skel_flush(struct file *file, fl_owner_t id)
	138	{
	139	struct usb_skel *dev;
	140	int res;
	141
	142	dev = (struct usb_skel *)file->private_data;
	143	if (dev == NULL)
	144	return -ENODEV;
	145
	146	/* wait for io to stop */
	147	mutex_lock(&dev->io_mutex);
	148	skel_draw_down(dev);
	149
	150	/* read out errors, leave subsequent opens a clean slate */
	151	spin_lock_irq(&dev->err_lock);
	152	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
	153	dev->errors = 0;
	154	spin_unlock_irq(&dev->err_lock);
	155
	156	mutex_unlock(&dev->io_mutex);
	157
	158	return res;
	159	}
	160
1da177e4 LT	161	static ssize_t skel_read(struct file file, char buffer, size_t count, loff_t *ppos)
	162	{
	163	struct usb_skel *dev;
c0704541	164	int retval;
1da177e4 LT	165	int bytes_read;
	166
	167	dev = (struct usb_skel *)file->private_data;
121e287c AS	168
	169	mutex_lock(&dev->io_mutex);
	170	if (!dev->interface) { /* disconnect() was called */
	171	retval = -ENODEV;
	172	goto exit;
	173	}
	174
1da177e4 LT	175	/* do a blocking bulk read to get data from the device */
	176	retval = usb_bulk_msg(dev->udev,
	177	usb_rcvbulkpipe(dev->udev, dev->bulk_in_endpointAddr),
	178	dev->bulk_in_buffer,
	179	min(dev->bulk_in_size, count),
	180	&bytes_read, 10000);
	181
	182	/* if the read was successful, copy the data to userspace */
	183	if (!retval) {
	184	if (copy_to_user(buffer, dev->bulk_in_buffer, bytes_read))
	185	retval = -EFAULT;
	186	else
	187	retval = bytes_read;
	188	}
	189
121e287c AS	190	exit:
121e287c AS	191	mutex_unlock(&dev->io_mutex);
1da177e4 LT	192	return retval;
	193	}
	194
7d12e780	195	static void skel_write_bulk_callback(struct urb *urb)
1da177e4 LT	196	{
	197	struct usb_skel *dev;
	198
	199	dev = (struct usb_skel *)urb->context;
	200
	201	/* sync/async unlink faults aren't errors */
403dfb58 ON	202	if (urb->status) {
	203	if(!(urb->status == -ENOENT \|\|
	204	urb->status == -ECONNRESET \|\|
	205	urb->status == -ESHUTDOWN))
	206	err("%s - nonzero write bulk status received: %d",
	207	__FUNCTION__, urb->status);
	208
	209	spin_lock(&dev->err_lock);
	210	dev->errors = urb->status;
	211	spin_unlock(&dev->err_lock);
1da177e4 LT	212	}
	213
	214	/* free up our allocated buffer */
c0704541	215	usb_buffer_free(urb->dev, urb->transfer_buffer_length,
1da177e4	216	urb->transfer_buffer, urb->transfer_dma);
ff906518	217	up(&dev->limit_sem);
1da177e4 LT	218	}
	219
	220	static ssize_t skel_write(struct file file, const char user_buffer, size_t count, loff_t *ppos)
	221	{
	222	struct usb_skel *dev;
	223	int retval = 0;
	224	struct urb *urb = NULL;
	225	char *buf = NULL;
c8dd7709	226	size_t writesize = min(count, (size_t)MAX_TRANSFER);
1da177e4 LT	227
	228	dev = (struct usb_skel *)file->private_data;
	229
	230	/* verify that we actually have some data to write */
	231	if (count == 0)
	232	goto exit;
	233
ff906518	234	/* limit the number of URBs in flight to stop a user from using up all RAM */
c8dd7709 SB	235	if (down_interruptible(&dev->limit_sem)) {
	236	retval = -ERESTARTSYS;
	237	goto exit;
	238	}
ff906518	239
403dfb58 ON	240	spin_lock_irq(&dev->err_lock);
	241	if ((retval = dev->errors) < 0) {
	242	/* any error is reported once */
	243	dev->errors = 0;
	244	/* to preserve notifications about reset */
	245	retval = (retval == -EPIPE) ? retval : -EIO;
	246	}
	247	spin_unlock_irq(&dev->err_lock);
	248	if (retval < 0)
	249	goto error;
	250
1da177e4 LT	251	/* create a urb, and a buffer for it, and copy the data to the urb */
	252	urb = usb_alloc_urb(0, GFP_KERNEL);
	253	if (!urb) {
	254	retval = -ENOMEM;
	255	goto error;
	256	}
	257
ff906518	258	buf = usb_buffer_alloc(dev->udev, writesize, GFP_KERNEL, &urb->transfer_dma);
1da177e4 LT	259	if (!buf) {
	260	retval = -ENOMEM;
	261	goto error;
	262	}
	263
ff906518	264	if (copy_from_user(buf, user_buffer, writesize)) {
1da177e4 LT	265	retval = -EFAULT;
	266	goto error;
	267	}
	268
ba35e02b ON	269	/* this lock makes sure we don't submit URBs to gone devices */
	270	mutex_lock(&dev->io_mutex);
	271	if (!dev->interface) { /* disconnect() was called */
	272	mutex_unlock(&dev->io_mutex);
	273	retval = -ENODEV;
	274	goto error;
	275	}
	276
1da177e4 LT	277	/* initialize the urb properly */
	278	usb_fill_bulk_urb(urb, dev->udev,
	279	usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
ff906518	280	buf, writesize, skel_write_bulk_callback, dev);
1da177e4	281	urb->transfer_flags \|= URB_NO_TRANSFER_DMA_MAP;
403dfb58	282	usb_anchor_urb(urb, &dev->submitted);
1da177e4 LT	283
	284	/* send the data out the bulk port */
	285	retval = usb_submit_urb(urb, GFP_KERNEL);
ba35e02b	286	mutex_unlock(&dev->io_mutex);
1da177e4 LT	287	if (retval) {
1da177e4 LT	288	err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
403dfb58	289	goto error_unanchor;
1da177e4 LT	290	}
	291
	292	/* release our reference to this urb, the USB core will eventually free it entirely */
	293	usb_free_urb(urb);
	294
ba35e02b	295
ff906518	296	return writesize;
1da177e4	297
403dfb58 ON	298	error_unanchor:
403dfb58 ON	299	usb_unanchor_urb(urb);
1da177e4	300	error:
121e287c AS	301	if (urb) {
	302	usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
	303	usb_free_urb(urb);
	304	}
ff906518	305	up(&dev->limit_sem);
121e287c AS	306
121e287c AS	307	exit:
1da177e4 LT	308	return retval;
	309	}
	310
066202dd	311	static const struct file_operations skel_fops = {
1da177e4 LT	312	.owner = THIS_MODULE,
	313	.read = skel_read,
	314	.write = skel_write,
	315	.open = skel_open,
	316	.release = skel_release,
403dfb58	317	.flush = skel_flush,
1da177e4 LT	318	};
1da177e4 LT	319
c0704541	320	/*
1da177e4	321	* usb class driver info in order to get a minor number from the usb core,
595b14cb	322	* and to have the device registered with the driver core
1da177e4 LT	323	*/
1da177e4 LT	324	static struct usb_class_driver skel_class = {
d6e5bcf4	325	.name = "skel%d",
1da177e4	326	.fops = &skel_fops,
1da177e4 LT	327	.minor_base = USB_SKEL_MINOR_BASE,
	328	};
	329
	330	static int skel_probe(struct usb_interface interface, const struct usb_device_id id)
	331	{
c0704541	332	struct usb_skel *dev;
1da177e4 LT	333	struct usb_host_interface *iface_desc;
	334	struct usb_endpoint_descriptor *endpoint;
	335	size_t buffer_size;
	336	int i;
	337	int retval = -ENOMEM;
	338
	339	/* allocate memory for our device state and initialize it */
ff906518	340	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
c0704541	341	if (!dev) {
1da177e4 LT	342	err("Out of memory");
	343	goto error;
	344	}
1da177e4	345	kref_init(&dev->kref);
ff906518	346	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
121e287c	347	mutex_init(&dev->io_mutex);
403dfb58 ON	348	spin_lock_init(&dev->err_lock);
403dfb58 ON	349	init_usb_anchor(&dev->submitted);
1da177e4 LT	350
	351	dev->udev = usb_get_dev(interface_to_usbdev(interface));
	352	dev->interface = interface;
	353
	354	/* set up the endpoint information */
	355	/* use only the first bulk-in and bulk-out endpoints */
	356	iface_desc = interface->cur_altsetting;
	357	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
	358	endpoint = &iface_desc->endpoint[i].desc;
	359
	360	if (!dev->bulk_in_endpointAddr &&
c0704541	361	usb_endpoint_is_bulk_in(endpoint)) {
1da177e4 LT	362	/* we found a bulk in endpoint */
	363	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
	364	dev->bulk_in_size = buffer_size;
	365	dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
	366	dev->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
	367	if (!dev->bulk_in_buffer) {
	368	err("Could not allocate bulk_in_buffer");
	369	goto error;
	370	}
	371	}
	372
	373	if (!dev->bulk_out_endpointAddr &&
c0704541	374	usb_endpoint_is_bulk_out(endpoint)) {
1da177e4 LT	375	/* we found a bulk out endpoint */
	376	dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
	377	}
	378	}
	379	if (!(dev->bulk_in_endpointAddr && dev->bulk_out_endpointAddr)) {
	380	err("Could not find both bulk-in and bulk-out endpoints");
	381	goto error;
	382	}
	383
	384	/* save our data pointer in this interface device */
	385	usb_set_intfdata(interface, dev);
	386
	387	/* we can register the device now, as it is ready */
	388	retval = usb_register_dev(interface, &skel_class);
	389	if (retval) {
	390	/* something prevented us from registering this driver */
	391	err("Not able to get a minor for this device.");
	392	usb_set_intfdata(interface, NULL);
	393	goto error;
	394	}
	395
	396	/* let the user know what node this device is now attached to */
	397	info("USB Skeleton device now attached to USBSkel-%d", interface->minor);
	398	return 0;
	399
	400	error:
	401	if (dev)
ba35e02b	402	/* this frees allocated memory */
1da177e4 LT	403	kref_put(&dev->kref, skel_delete);
	404	return retval;
	405	}
	406
	407	static void skel_disconnect(struct usb_interface *interface)
	408	{
	409	struct usb_skel *dev;
	410	int minor = interface->minor;
	411
1da177e4 LT	412	dev = usb_get_intfdata(interface);
	413	usb_set_intfdata(interface, NULL);
	414
	415	/* give back our minor */
	416	usb_deregister_dev(interface, &skel_class);
	417
121e287c AS	418	/* prevent more I/O from starting */
	419	mutex_lock(&dev->io_mutex);
	420	dev->interface = NULL;
	421	mutex_unlock(&dev->io_mutex);
	422
e73c7247 ON	423	usb_kill_anchored_urbs(&dev->submitted);
e73c7247 ON	424
1da177e4 LT	425	/* decrement our usage count */
	426	kref_put(&dev->kref, skel_delete);
	427
	428	info("USB Skeleton #%d now disconnected", minor);
	429	}
	430
403dfb58 ON	431	static void skel_draw_down(struct usb_skel *dev)
	432	{
	433	int time;
	434
	435	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
	436	if (!time)
	437	usb_kill_anchored_urbs(&dev->submitted);
	438	}
	439
1da177e4	440	static struct usb_driver skel_driver = {
1da177e4 LT	441	.name = "skeleton",
	442	.probe = skel_probe,
	443	.disconnect = skel_disconnect,
	444	.id_table = skel_table,
ba35e02b	445	.supports_autosuspend = 1,
1da177e4 LT	446	};
	447
	448	static int __init usb_skel_init(void)
	449	{
	450	int result;
	451
	452	/* register this driver with the USB subsystem */
	453	result = usb_register(&skel_driver);
	454	if (result)
	455	err("usb_register failed. Error number %d", result);
	456
	457	return result;
	458	}
	459
	460	static void __exit usb_skel_exit(void)
	461	{
	462	/* deregister this driver with the USB subsystem */
	463	usb_deregister(&skel_driver);
	464	}
	465
c0704541 LFC	466	module_init(usb_skel_init);
c0704541 LFC	467	module_exit(usb_skel_exit);
1da177e4 LT	468
1da177e4 LT	469	MODULE_LICENSE("GPL");