usb.c

linux下的USB主机端骨架程序

		      skel_read_bulk_callback, dev);

	/* send the data out the bulk port */
	retval = usb_submit_urb(dev->read_urb);
	//***Wait queue
	printk("The READ function go into wait queue!\n");
	interruptible_sleep_on(&rwq);
	printk("The READ function wake up!\n");
	/* if the read was successful, copy the data to userspace */
	if (!retval) {
		printk("@@@@@@@@@ Read success ! =%s\n",dev->bulk_in_buffer);
	//**Get the bytes that has been transfered!
		count = dev->read_urb->actual_length;
		if (copy_to_user (buffer, dev->bulk_in_buffer, count))
			retval = -EFAULT;
		else
			retval = count;
	}
	
	/* unlock the device */
	up (&dev->sem);
	return retval;
}


/**
 *	skel_write
 */
static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
{
	struct usb_skel *dev;
	ssize_t bytes_written = 0;
	int retval = 0;

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

//	dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count);

	/* lock this object */
	down (&dev->sem);

	/* verify that the device wasn't unplugged */
	if (dev->udev == NULL) {
		retval = -ENODEV;
		goto exit;
	}

	/* verify that we actually have some data to write */
	if (count == 0) {
//		dbg(__FUNCTION__ " - write request of 0 bytes");
		goto exit;
	}

	/* see if we are already in the middle of a write */
	if (dev->write_urb->status == -EINPROGRESS) {
//		dbg (__FUNCTION__ " - already writing");
		goto exit;
	}

	/* we can only write as much as 1 urb will hold */
	bytes_written = (count > dev->bulk_out_size) ? 
				dev->bulk_out_size : count;

	/* copy the data from userspace into our urb */
	if (copy_from_user(dev->write_urb->transfer_buffer, buffer, 
			   bytes_written)) {
		retval = -EFAULT;
		goto exit;
	}

//	usb_skel_debug_data (__FUNCTION__, bytes_written, 
//			     dev->write_urb->transfer_buffer);

	/* set up our urb */
	usb_fill_bulk_urb(dev->write_urb, dev->udev, 
		      usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
		      dev->write_urb->transfer_buffer, bytes_written,
		      skel_write_bulk_callback, dev);

	/* send the data out the bulk port */
	retval = usb_submit_urb(dev->write_urb);
	//*** Wait queue
	printk("The WRITE function go into wait queue!\n");
	interruptible_sleep_on(&wwq);
	printk("The WROTE function wake up!\n");

	if (retval) {
//		err(__FUNCTION__ " - failed submitting write urb, error %d",
//		    retval);
		retval = -1;
	} else {
		retval = dev->write_urb->actual_length;
	}

exit:
	/* unlock the device */
	up (&dev->sem);

	return retval;
}


/**
 *	skel_ioctl
 */
static int skel_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	struct usb_skel *dev;

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

	/* lock this object */
	down (&dev->sem);

	/* verify that the device wasn't unplugged */
	if (dev->udev == NULL) {
		up (&dev->sem);
		return -ENODEV;
	}

//	dbg(__FUNCTION__ " - minor %d, cmd 0x%.4x, arg %ld", 
//	    dev->minor, cmd, arg);


	/* fill in your device specific stuff here */
	
	/* unlock the device */
	up (&dev->sem);
	
	/* return that we did not understand this ioctl call */
	return -ENOTTY;
}


/**
 *	skel_write_bulk_callback
 */
static void skel_write_bulk_callback (struct urb *urb)
{
	printk("The *write* recall has been called!\n");
	wake_up_interruptible(&wwq);
	
	struct usb_skel *dev = (struct usb_skel *)urb->context;

//	dbg(__FUNCTION__ " - minor %d", dev->minor);

	if ((urb->status != -ENOENT) && 
	    (urb->status != -ECONNRESET)) {
//		dbg(__FUNCTION__ " - nonzero write bulk status received: %d",
//		    urb->status);
		return ;
	}

	return;
}


/**
 *	skel_read_bulk_callback
 */
static void skel_read_bulk_callback (struct urb *urb)
{
	printk("The *read* recall has been called!\n");
	wake_up_interruptible(&rwq);

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

//	dbg(__FUNCTION__ " - minor %d", dev->minor);

	if ((urb->status != -ENOENT) && 
	    (urb->status != -ECONNRESET)) {
//		dbg(__FUNCTION__ " - nonzero write bulk status received: %d",
//		    urb->status);
		return ;
	}

	return;
}
/**
 *	skel_probe
 *
 *	Called by the usb core when a new device is connected that it thinks
 *	this driver might be interested in.
 */
static void * skel_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id)
{
	printk("###The probe function has been called !###\n");

	struct usb_skel *dev = NULL;
	struct usb_interface *interface;
	struct usb_interface_descriptor *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	int minor;
	int buffer_size;
	int i;
	char name[10];

	
	/* See if the device offered us matches what we can accept */
	if ((udev->descriptor.idVendor != USB_SKEL_VENDOR_ID) ||
	    (udev->descriptor.idProduct != USB_SKEL_PRODUCT_ID)) {
		return NULL;
	}

	/* select a "subminor" number (part of a minor number) */
	down (&minor_table_mutex);
	for (minor = 0; minor < MAX_DEVICES; ++minor) {
		if (minor_table[minor] == NULL)
			break;
	}
	if (minor >= MAX_DEVICES) {
		info ("Too many devices plugged in, can not handle this device.");
		goto exit;
	}

	/* allocate memory for our device state and intialize it */
	dev = kmalloc (sizeof(struct usb_skel), GFP_KERNEL);
	if (dev == NULL) {
		err ("Out of memory");
		goto exit;
	}
	memset (dev, 0x00, sizeof (*dev));
	minor_table[minor] = dev;

	interface = &udev->actconfig->interface[ifnum];

	init_MUTEX (&dev->sem);
	dev->udev = udev;
	dev->interface = interface;
	dev->minor = minor;

	/* set up the endpoint information */
	/* check out the endpoints */
	iface_desc = &interface->altsetting[0];
	for (i = 0; i < iface_desc->bNumEndpoints; ++i) {
		
		endpoint = &iface_desc->endpoint[i];

		if ((endpoint->bEndpointAddress & 0x80) &&
		    ((endpoint->bmAttributes & 3) == 0x02)) {
			/* we found a bulk in endpoint */
			dev->read_urb = usb_alloc_urb(0);
			if (!dev->read_urb) {
				err("No free urbs available");
				goto error;
			}
			buffer_size = 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("Couldn't allocate bulk_in_buffer");
				goto error;
			}
			usb_fill_bulk_urb(dev->read_urb, udev, 
				      usb_rcvbulkpipe(udev, 
				      endpoint->bEndpointAddress),
				      dev->bulk_in_buffer, buffer_size,
				      skel_read_bulk_callback, dev);
		}
		
		if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
		    ((endpoint->bmAttributes & 3) == 0x02)) {
			/* we found a bulk out endpoint */
			dev->write_urb = usb_alloc_urb(0);
			if (!dev->write_urb) {
				err("No free urbs available");
				goto error;
			}
			buffer_size = endpoint->wMaxPacketSize;
			dev->bulk_out_size = buffer_size;
			dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
			dev->bulk_out_buffer = kmalloc (buffer_size, GFP_KERNEL);
			if (!dev->bulk_out_buffer) {
				err("Couldn't allocate bulk_out_buffer");
				goto error;
			}
			usb_fill_bulk_urb(dev->write_urb, udev, 
				      usb_sndbulkpipe(udev, 
				      endpoint->bEndpointAddress),
				      dev->bulk_out_buffer, buffer_size,
				      skel_write_bulk_callback, dev);

		      		      }
	}

	/* initialize the devfs node for this device and register it */
	sprintf(name, "skel%d", dev->minor);
	
	dev->devfs = devfs_register (usb_devfs_handle, name,
				     DEVFS_FL_DEFAULT, USB_MAJOR,
				     USB_SKEL_MINOR_BASE + dev->minor,
				     S_IFCHR | S_IRUSR | S_IWUSR | 
				     S_IRGRP | S_IWGRP | S_IROTH, 
				     &skel_fops, NULL);

	/* let the user know what node this device is now attached to */
	info ("USB Skeleton device now attached to USBSkel%d", dev->minor);
	goto exit;
	
error:
	skel_delete (dev);
	dev = NULL;

exit:
	up (&minor_table_mutex);
	return dev;
}


/**
 *	skel_disconnect
 *
 *	Called by the usb core when the device is removed from the system.
 */
static void skel_disconnect(struct usb_device *udev, void *ptr)
{
	struct usb_skel *dev;
	int minor;

	dev = (struct usb_skel *)ptr;
	
	down (&minor_table_mutex);
	down (&dev->sem);
		
	minor = dev->minor;

	/* remove our devfs node */
	devfs_unregister(dev->devfs);

	/* if the device is not opened, then we clean up right now */
	if (!dev->open_count) {
		up (&dev->sem);
		skel_delete (dev);
	} else {
		dev->udev = NULL;
		up (&dev->sem);
	}

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



/**
 *	usb_skel_init
 */
static int __init usb_skel_init(void)
{
	int result;

	/* register this driver with the USB subsystem */
	result = usb_register(&skel_driver);
	if (result < 0) {
		err("usb_register failed for the "__FILE__" driver. Error number %d",
		    result);
		return -1;
	}

	info(DRIVER_DESC " " DRIVER_VERSION);
	return 0;
}


/**
 *	usb_skel_exit
 */
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_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");