/* * USB Skeleton driver - 2.0 * * 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 easy to read and use, as no locks are now * needed anymore. * */#include <linux/config.h>#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>/* 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 )#define WRITES_IN_FLIGHT	8/* 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;};#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);	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);	/* 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;	/* 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 = 0;	int bytes_read;	dev = (struct usb_skel *)file->private_data;		/* 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;	}	return retval;}static void skel_write_bulk_callback(struct urb *urb, struct pt_regs *regs){	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)) {		dbg("%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;	}	/* 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);	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);exit:	return writesize;error:	usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);	usb_free_urb(urb);	up(&dev->limit_sem);	return retval;}static 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 = NULL;	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 == NULL) {		err("Out of memory");		goto error;	}	kref_init(&dev->kref);	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);	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 &&		    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)					== USB_DIR_IN) &&		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)					== USB_ENDPOINT_XFER_BULK)) {			/* 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 &&		    ((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK)					== USB_DIR_OUT) &&		    ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)					== USB_ENDPOINT_XFER_BULK)) {			/* 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)		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() */	lock_kernel();	dev = usb_get_intfdata(interface);	usb_set_intfdata(interface, NULL);	/* give back our minor */	usb_deregister_dev(interface, &skel_class);	unlock_kernel();	/* 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,};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");