adutux.c

linux 内核源代码

				dev->read_buffer_primary = tmp;
				dev->secondary_head = 0;
				dev->secondary_tail = dev->read_buffer_length;
				dev->read_buffer_length = 0;
				spin_unlock_irqrestore(&dev->buflock, flags);
				/* we have a free buffer so use it */
				should_submit = 1;
			} else {
				/* even the primary was empty - we may need to do IO */
				if (!dev->read_urb_finished) {
					/* somebody is doing IO */
					spin_unlock_irqrestore(&dev->buflock, flags);
					dbg(2," %s : submitted already", __FUNCTION__);
				} else {
					/* we must initiate input */
					dbg(2," %s : initiate input", __FUNCTION__);
					dev->read_urb_finished = 0;
					spin_unlock_irqrestore(&dev->buflock, flags);

					usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
							 usb_rcvintpipe(dev->udev,
							 		dev->interrupt_in_endpoint->bEndpointAddress),
							 dev->interrupt_in_buffer,
							 le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
							 adu_interrupt_in_callback,
							 dev,
							 dev->interrupt_in_endpoint->bInterval);
					retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
					if (retval) {
						dev->read_urb_finished = 1;
						if (retval == -ENOMEM) {
							retval = bytes_read ? bytes_read : -ENOMEM;
						}
						dbg(2," %s : submit failed", __FUNCTION__);
						goto exit;
					}
				}

				/* we wait for I/O to complete */
				set_current_state(TASK_INTERRUPTIBLE);
				add_wait_queue(&dev->read_wait, &wait);
				spin_lock_irqsave(&dev->buflock, flags);
				if (!dev->read_urb_finished) {
					spin_unlock_irqrestore(&dev->buflock, flags);
					timeout = schedule_timeout(COMMAND_TIMEOUT);
				} else {
					spin_unlock_irqrestore(&dev->buflock, flags);
					set_current_state(TASK_RUNNING);
				}
				remove_wait_queue(&dev->read_wait, &wait);

				if (timeout <= 0) {
					dbg(2," %s : timeout", __FUNCTION__);
					retval = bytes_read ? bytes_read : -ETIMEDOUT;
					goto exit;
				}

				if (signal_pending(current)) {
					dbg(2," %s : signal pending", __FUNCTION__);
					retval = bytes_read ? bytes_read : -EINTR;
					goto exit;
				}
			}
		}
	}

	retval = bytes_read;
	/* if the primary buffer is empty then use it */
	spin_lock_irqsave(&dev->buflock, flags);
	if (should_submit && dev->read_urb_finished) {
		dev->read_urb_finished = 0;
		spin_unlock_irqrestore(&dev->buflock, flags);
		usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
				 usb_rcvintpipe(dev->udev,
				 		dev->interrupt_in_endpoint->bEndpointAddress),
				dev->interrupt_in_buffer,
				le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
				adu_interrupt_in_callback,
				dev,
				dev->interrupt_in_endpoint->bInterval);
		if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL) != 0)
			dev->read_urb_finished = 1;
		/* we ignore failure */
	} else {
		spin_unlock_irqrestore(&dev->buflock, flags);
	}

exit:
	/* unlock the device */
	mutex_unlock(&dev->mtx);

	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
	return retval;
}

static ssize_t adu_write(struct file *file, const __user char *buffer,
			 size_t count, loff_t *ppos)
{
	DECLARE_WAITQUEUE(waita, current);
	struct adu_device *dev;
	size_t bytes_written = 0;
	size_t bytes_to_write;
	size_t buffer_size;
	unsigned long flags;
	int retval;

	dbg(2," %s : enter, count = %Zd", __FUNCTION__, count);

	dev = file->private_data;

	retval = mutex_lock_interruptible(&dev->mtx);
	if (retval)
		goto exit_nolock;

	/* verify that the device wasn't unplugged */
	if (dev->udev == NULL) {
		retval = -ENODEV;
		err("No device or device unplugged %d", retval);
		goto exit;
	}

	/* verify that we actually have some data to write */
	if (count == 0) {
		dbg(1," %s : write request of 0 bytes", __FUNCTION__);
		goto exit;
	}

	while (count > 0) {
		add_wait_queue(&dev->write_wait, &waita);
		set_current_state(TASK_INTERRUPTIBLE);
		spin_lock_irqsave(&dev->buflock, flags);
		if (!dev->out_urb_finished) {
			spin_unlock_irqrestore(&dev->buflock, flags);

			mutex_unlock(&dev->mtx);
			if (signal_pending(current)) {
				dbg(1," %s : interrupted", __FUNCTION__);
				set_current_state(TASK_RUNNING);
				retval = -EINTR;
				goto exit_onqueue;
			}
			if (schedule_timeout(COMMAND_TIMEOUT) == 0) {
				dbg(1, "%s - command timed out.", __FUNCTION__);
				retval = -ETIMEDOUT;
				goto exit_onqueue;
			}
			remove_wait_queue(&dev->write_wait, &waita);
			retval = mutex_lock_interruptible(&dev->mtx);
			if (retval) {
				retval = bytes_written ? bytes_written : retval;
				goto exit_nolock;
			}

			dbg(4," %s : in progress, count = %Zd", __FUNCTION__, count);
		} else {
			spin_unlock_irqrestore(&dev->buflock, flags);
			set_current_state(TASK_RUNNING);
			remove_wait_queue(&dev->write_wait, &waita);
			dbg(4," %s : sending, count = %Zd", __FUNCTION__, count);

			/* write the data into interrupt_out_buffer from userspace */
			buffer_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);
			bytes_to_write = count > buffer_size ? buffer_size : count;
			dbg(4," %s : buffer_size = %Zd, count = %Zd, bytes_to_write = %Zd",
			    __FUNCTION__, buffer_size, count, bytes_to_write);

			if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write) != 0) {
				retval = -EFAULT;
				goto exit;
			}

			/* send off the urb */
			usb_fill_int_urb(
				dev->interrupt_out_urb,
				dev->udev,
				usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
				dev->interrupt_out_buffer,
				bytes_to_write,
				adu_interrupt_out_callback,
				dev,
				dev->interrupt_out_endpoint->bInterval);
			dev->interrupt_out_urb->actual_length = bytes_to_write;
			dev->out_urb_finished = 0;
			retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
			if (retval < 0) {
				dev->out_urb_finished = 1;
				err("Couldn't submit interrupt_out_urb %d", retval);
				goto exit;
			}

			buffer += bytes_to_write;
			count -= bytes_to_write;

			bytes_written += bytes_to_write;
		}
	}
	mutex_unlock(&dev->mtx);
	return bytes_written;

exit:
	mutex_unlock(&dev->mtx);
exit_nolock:
	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
	return retval;

exit_onqueue:
	remove_wait_queue(&dev->write_wait, &waita);
	return retval;
}

/* file operations needed when we register this driver */
static const struct file_operations adu_fops = {
	.owner = THIS_MODULE,
	.read  = adu_read,
	.write = adu_write,
	.open = adu_open,
	.release = adu_release,
};

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

/**
 * adu_probe
 *
 * Called by the usb core when a new device is connected that it thinks
 * this driver might be interested in.
 */
static int adu_probe(struct usb_interface *interface,
		     const struct usb_device_id *id)
{
	struct usb_device *udev = interface_to_usbdev(interface);
	struct adu_device *dev = NULL;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	int retval = -ENODEV;
	int in_end_size;
	int out_end_size;
	int i;

	dbg(2," %s : enter", __FUNCTION__);

	if (udev == NULL) {
		dev_err(&interface->dev, "udev is NULL.\n");
		goto exit;
	}

	/* allocate memory for our device state and intialize it */
	dev = kzalloc(sizeof(struct adu_device), GFP_KERNEL);
	if (dev == NULL) {
		dev_err(&interface->dev, "Out of memory\n");
		retval = -ENOMEM;
		goto exit;
	}

	mutex_init(&dev->mtx);
	spin_lock_init(&dev->buflock);
	dev->udev = udev;
	init_waitqueue_head(&dev->read_wait);
	init_waitqueue_head(&dev->write_wait);

	iface_desc = &interface->altsetting[0];

	/* set up the endpoint information */
	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
		endpoint = &iface_desc->endpoint[i].desc;

		if (usb_endpoint_is_int_in(endpoint))
			dev->interrupt_in_endpoint = endpoint;

		if (usb_endpoint_is_int_out(endpoint))
			dev->interrupt_out_endpoint = endpoint;
	}
	if (dev->interrupt_in_endpoint == NULL) {
		dev_err(&interface->dev, "interrupt in endpoint not found\n");
		goto error;
	}
	if (dev->interrupt_out_endpoint == NULL) {
		dev_err(&interface->dev, "interrupt out endpoint not found\n");
		goto error;
	}

	in_end_size = le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
	out_end_size = le16_to_cpu(dev->interrupt_out_endpoint->wMaxPacketSize);

	dev->read_buffer_primary = kmalloc((4 * in_end_size), GFP_KERNEL);
	if (!dev->read_buffer_primary) {
		dev_err(&interface->dev, "Couldn't allocate read_buffer_primary\n");
		retval = -ENOMEM;
		goto error;
	}

	/* debug code prime the buffer */
	memset(dev->read_buffer_primary, 'a', in_end_size);
	memset(dev->read_buffer_primary + in_end_size, 'b', in_end_size);
	memset(dev->read_buffer_primary + (2 * in_end_size), 'c', in_end_size);
	memset(dev->read_buffer_primary + (3 * in_end_size), 'd', in_end_size);

	dev->read_buffer_secondary = kmalloc((4 * in_end_size), GFP_KERNEL);
	if (!dev->read_buffer_secondary) {
		dev_err(&interface->dev, "Couldn't allocate read_buffer_secondary\n");
		retval = -ENOMEM;
		goto error;
	}

	/* debug code prime the buffer */
	memset(dev->read_buffer_secondary, 'e', in_end_size);
	memset(dev->read_buffer_secondary + in_end_size, 'f', in_end_size);
	memset(dev->read_buffer_secondary + (2 * in_end_size), 'g', in_end_size);
	memset(dev->read_buffer_secondary + (3 * in_end_size), 'h', in_end_size);

	dev->interrupt_in_buffer = kmalloc(in_end_size, GFP_KERNEL);
	if (!dev->interrupt_in_buffer) {
		dev_err(&interface->dev, "Couldn't allocate interrupt_in_buffer\n");
		goto error;
	}

	/* debug code prime the buffer */
	memset(dev->interrupt_in_buffer, 'i', in_end_size);

	dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->interrupt_in_urb) {
		dev_err(&interface->dev, "Couldn't allocate interrupt_in_urb\n");
		goto error;
	}
	dev->interrupt_out_buffer = kmalloc(out_end_size, GFP_KERNEL);
	if (!dev->interrupt_out_buffer) {
		dev_err(&interface->dev, "Couldn't allocate interrupt_out_buffer\n");
		goto error;
	}
	dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->interrupt_out_urb) {
		dev_err(&interface->dev, "Couldn't allocate interrupt_out_urb\n");
		goto error;
	}

	if (!usb_string(udev, udev->descriptor.iSerialNumber, dev->serial_number,
			sizeof(dev->serial_number))) {
		dev_err(&interface->dev, "Could not retrieve serial number\n");
		goto error;
	}
	dbg(2," %s : serial_number=%s", __FUNCTION__, dev->serial_number);

	/* we can register the device now, as it is ready */
	usb_set_intfdata(interface, dev);

	retval = usb_register_dev(interface, &adu_class);

	if (retval) {
		/* something prevented us from registering this driver */
		dev_err(&interface->dev, "Not able to get a minor for this device.\n");
		usb_set_intfdata(interface, NULL);
		goto error;
	}

	dev->minor = interface->minor;

	/* let the user know what node this device is now attached to */
	dev_info(&interface->dev, "ADU%d %s now attached to /dev/usb/adutux%d\n",
		 udev->descriptor.idProduct, dev->serial_number,
		 (dev->minor - ADU_MINOR_BASE));
exit:
	dbg(2," %s : leave, return value %p (dev)", __FUNCTION__, dev);

	return retval;

error:
	adu_delete(dev);
	return retval;
}

/**
 * adu_disconnect
 *
 * Called by the usb core when the device is removed from the system.
 */
static void adu_disconnect(struct usb_interface *interface)
{
	struct adu_device *dev;
	int minor;

	dbg(2," %s : enter", __FUNCTION__);

	dev = usb_get_intfdata(interface);

	mutex_lock(&dev->mtx);	/* not interruptible */
	dev->udev = NULL;	/* poison */
	minor = dev->minor;
	usb_deregister_dev(interface, &adu_class);
	mutex_unlock(&dev->mtx);

	mutex_lock(&adutux_mutex);
	usb_set_intfdata(interface, NULL);

	/* if the device is not opened, then we clean up right now */
	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
	if (!dev->open_count)
		adu_delete(dev);

	mutex_unlock(&adutux_mutex);

	dev_info(&interface->dev, "ADU device adutux%d now disconnected\n",
		 (minor - ADU_MINOR_BASE));

	dbg(2," %s : leave", __FUNCTION__);
}

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver adu_driver = {
	.name = "adutux",
	.probe = adu_probe,
	.disconnect = adu_disconnect,
	.id_table = device_table,
};

static int __init adu_init(void)
{
	int result;

	dbg(2," %s : enter", __FUNCTION__);

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

	info("adutux " DRIVER_DESC " " DRIVER_VERSION);
	info("adutux is an experimental driver. Use at your own risk");

exit:
	dbg(2," %s : leave, return value %d", __FUNCTION__, result);

	return result;
}

static void __exit adu_exit(void)
{
	dbg(2," %s : enter", __FUNCTION__);
	/* deregister this driver with the USB subsystem */
	usb_deregister(&adu_driver);
	dbg(2," %s : leave", __FUNCTION__);
}

module_init(adu_init);
module_exit(adu_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");