printer.c

linux qt class 类的函数定义

 * don't attempt any bulk IN transfers from the IN endpoint.
 * Here's some more detail on the problem:
 * The problem is not that it isn't bidirectional though. The problem
 * is that if you request a device ID, or status information, while
 * the buffers are full, the return data will end up in the print data
 * buffer. For example if you make sure you never request the device ID
 * while you are sending print data, and you don't try to query the
 * printer status every couple of milliseconds, you will probably be OK.
 */
static unsigned int usblp_quirks (__u16 vendor, __u16 product)
{
	int i;

	for (i = 0; quirk_printers[i].vendorId; i++) {
		if (vendor == quirk_printers[i].vendorId &&
		    product == quirk_printers[i].productId)
			return quirk_printers[i].quirks;
 	}
	return 0;
}

static struct file_operations usblp_fops = {
	owner:		THIS_MODULE,
	read:		usblp_read,
	write:		usblp_write,
	poll:		usblp_poll,
	ioctl:		usblp_ioctl,
	open:		usblp_open,
	release:	usblp_release,
};

static void *usblp_probe(struct usb_device *dev, unsigned int ifnum,
			 const struct usb_device_id *id)
{
	struct usblp *usblp = 0;
	int protocol;
	int retval;
	char name[6];

	/* Malloc and start initializing usblp structure so we can use it
	 * directly. */
	if (!(usblp = kmalloc(sizeof(struct usblp), GFP_KERNEL))) {
		err("out of memory for usblp");
		goto abort;
	}
	memset(usblp, 0, sizeof(struct usblp));
	usblp->dev = dev;
	init_MUTEX (&usblp->sem);
	init_waitqueue_head(&usblp->wait);
	usblp->ifnum = ifnum;

	retval = usb_register_dev(&usblp_driver, 1, &usblp->minor);
	if (retval) {
		if (retval != -ENODEV) {
			err("Not able to get a minor for this device.");
			goto abort;
		}
		/* Look for a free usblp_table entry on our own. */
		while (usblp_table[usblp->minor]) {
			usblp->minor++;
			if (usblp->minor >= USBLP_MINORS) {
				err("no more free usblp devices");
				goto abort;
			}
		}
	}

	usblp->writeurb = usb_alloc_urb(0, GFP_KERNEL);
	if (!usblp->writeurb) {
		err("out of memory");
		goto abort_minor;
	}
	usblp->readurb = usb_alloc_urb(0, GFP_KERNEL);
	if (!usblp->readurb) {
		err("out of memory");
		goto abort_minor;
	}

	/* Malloc device ID string buffer to the largest expected length,
	 * since we can re-query it on an ioctl and a dynamic string
	 * could change in length. */
	if (!(usblp->device_id_string = kmalloc(DEVICE_ID_SIZE, GFP_KERNEL))) {
		err("out of memory for device_id_string");
		goto abort_minor;
	}

	/* Malloc write/read buffers in one chunk.  We somewhat wastefully
	 * malloc both regardless of bidirectionality, because the
	 * alternate setting can be changed later via an ioctl. */
	if (!(usblp->buf = kmalloc(2 * USBLP_BUF_SIZE, GFP_KERNEL))) {
		err("out of memory for buf");
		goto abort_minor;
	}

	/* Lookup quirks for this printer. */
	usblp->quirks = usblp_quirks(
		dev->descriptor.idVendor,
		dev->descriptor.idProduct);

	/* Analyze and pick initial alternate settings and endpoints. */
	protocol = usblp_select_alts(usblp);
	if (protocol < 0) {
		dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
			dev->descriptor.idVendor,
			dev->descriptor.idProduct);
		goto abort_minor;
	}

	/* Setup the selected alternate setting and endpoints. */
	if (usblp_set_protocol(usblp, protocol) < 0)
		goto abort_minor;

	/* Retrieve and store the device ID string. */
	usblp_cache_device_id_string(usblp);

#ifdef DEBUG
	usblp_check_status(usblp, 0);
#endif

	/* add a table entry so the device works when advertised */
	usblp_table[usblp->minor] = usblp;

	/* If we have devfs, create with perms=660. */
	sprintf(name, "lp%d", usblp->minor);
	usblp->devfs = devfs_register(usb_devfs_handle, name,
				      DEVFS_FL_DEFAULT, USB_MAJOR,
				      USBLP_MINOR_BASE + usblp->minor,
				      S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP |
				      S_IWGRP, &usblp_fops, NULL);

	info("usblp%d: USB %sdirectional printer dev %d "
		"if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X",
		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum, ifnum,
		usblp->protocol[usblp->current_protocol].alt_setting,
		usblp->current_protocol, usblp->dev->descriptor.idVendor,
		usblp->dev->descriptor.idProduct);

	return usblp;

abort_minor:
	usb_deregister_dev (&usblp_driver, 1, usblp->minor);
abort:
	if (usblp) {
		usb_free_urb(usblp->writeurb);
		usb_free_urb(usblp->readurb);
		if (usblp->buf) kfree(usblp->buf);
		if (usblp->device_id_string) kfree(usblp->device_id_string);
		kfree(usblp);
	}
	return NULL;
}

/*
 * We are a "new" style driver with usb_device_id table,
 * but our requirements are too intricate for simple match to handle.
 *
 * The "proto_bias" option may be used to specify the preferred protocol
 * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
 * supports the preferred protocol, then we bind to it.
 *
 * The best interface for us is 7/1/2, because it is compatible
 * with a stream of characters. If we find it, we bind to it.
 *
 * Note that the people from hpoj.sourceforge.net need to be able to
 * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
 *
 * Failing 7/1/2, we look for 7/1/3, even though it's probably not
 * stream-compatible, because this matches the behaviour of the old code.
 *
 * If nothing else, we bind to 7/1/1 - the unidirectional interface.
 */
static int usblp_select_alts(struct usblp *usblp)
{
	struct usb_interface *if_alt;
	struct usb_interface_descriptor *ifd;
	struct usb_endpoint_descriptor *epd, *epwrite, *epread;
	int p, i, e;

	if_alt = &usblp->dev->actconfig->interface[usblp->ifnum];

	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
		usblp->protocol[p].alt_setting = -1;

	/* Find out what we have. */
	for (i = 0; i < if_alt->num_altsetting; i++) {
		ifd = &if_alt->altsetting[i];

		if (ifd->bInterfaceClass != 7 || ifd->bInterfaceSubClass != 1)
			continue;

		if (ifd->bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
		    ifd->bInterfaceProtocol > USBLP_LAST_PROTOCOL)
			continue;

		/* Look for bulk OUT and IN endpoints. */
		epwrite = epread = 0;
		for (e = 0; e < ifd->bNumEndpoints; e++) {
			epd = &ifd->endpoint[e];

			if ((epd->bmAttributes&USB_ENDPOINT_XFERTYPE_MASK)!=
			    USB_ENDPOINT_XFER_BULK)
				continue;

			if (!(epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK)) {
				if (!epwrite) epwrite=epd;

			} else {
				if (!epread) epread=epd;
			}
		}

		/* Ignore buggy hardware without the right endpoints. */
		if (!epwrite || (ifd->bInterfaceProtocol > 1 && !epread))
			continue;

		/* Turn off reads for 7/1/1 (unidirectional) interfaces
		 * and buggy bidirectional printers. */
		if (ifd->bInterfaceProtocol == 1) {
			epread = NULL;
		} else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
			info("Disabling reads from problem bidirectional "
				"printer on usblp%d", usblp->minor);
			epread = NULL;
		}

		usblp->protocol[ifd->bInterfaceProtocol].alt_setting = i;
		usblp->protocol[ifd->bInterfaceProtocol].epwrite = epwrite;
		usblp->protocol[ifd->bInterfaceProtocol].epread = epread;
	}

	/* If our requested protocol is supported, then use it. */
	if (proto_bias >= USBLP_FIRST_PROTOCOL &&
	    proto_bias <= USBLP_LAST_PROTOCOL &&
	    usblp->protocol[proto_bias].alt_setting != -1)
		return proto_bias;

	/* Ordering is important here. */
	if (usblp->protocol[2].alt_setting != -1) return 2;
	if (usblp->protocol[1].alt_setting != -1) return 1;
	if (usblp->protocol[3].alt_setting != -1) return 3;

	/* If nothing is available, then don't bind to this device. */
	return -1;
}

static int usblp_set_protocol(struct usblp *usblp, int protocol)
{
	int r, alts;

	if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
		return -EINVAL;

	alts = usblp->protocol[protocol].alt_setting;
	if (alts < 0) return -EINVAL;
	r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
	if (r < 0) {
		err("can't set desired altsetting %d on interface %d",
			alts, usblp->ifnum);
		return r;
	}

	FILL_BULK_URB(usblp->writeurb, usblp->dev,
		usb_sndbulkpipe(usblp->dev,
		 usblp->protocol[protocol].epwrite->bEndpointAddress),
		usblp->buf, 0,
		usblp_bulk_write, usblp);

	usblp->bidir = (usblp->protocol[protocol].epread != 0);
	if (usblp->bidir)
		FILL_BULK_URB(usblp->readurb, usblp->dev,
			usb_rcvbulkpipe(usblp->dev,
			 usblp->protocol[protocol].epread->bEndpointAddress),
			usblp->buf + USBLP_BUF_SIZE, USBLP_BUF_SIZE,
			usblp_bulk_read, usblp);

	usblp->current_protocol = protocol;
	dbg("usblp%d set protocol %d", usblp->minor, protocol);
	return 0;
}

/* Retrieves and caches device ID string.
 * Returns length, including length bytes but not null terminator.
 * On error, returns a negative errno value. */
static int usblp_cache_device_id_string(struct usblp *usblp)
{
	int err, length;

	err = usblp_get_id(usblp, 0, usblp->device_id_string, DEVICE_ID_SIZE - 1);
	if (err < 0) {
		dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
			usblp->minor, err);
		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
		return -EIO;
	}

	/* First two bytes are length in big-endian.
	 * They count themselves, and we copy them into
	 * the user's buffer. */
	length = (usblp->device_id_string[0] << 8) + usblp->device_id_string[1];
	if (length < 2)
		length = 2;
	else if (length >= DEVICE_ID_SIZE)
		length = DEVICE_ID_SIZE - 1;
	usblp->device_id_string[length] = '\0';

	dbg("usblp%d Device ID string [len=%d]=\"%s\"",
		usblp->minor, length, &usblp->device_id_string[2]);

	return length;
}

static void usblp_disconnect(struct usb_device *dev, void *ptr)
{
	struct usblp *usblp = ptr;

	if (!usblp || !usblp->dev) {
		err("bogus disconnect");
		BUG ();
	}

	down (&usblp->sem);
	lock_kernel();
	usblp->dev = NULL;

	usblp_unlink_urbs(usblp);

	if (!usblp->used)
		usblp_cleanup (usblp);
	else 	/* cleanup later, on close */
		up (&usblp->sem);
	unlock_kernel();
}

static struct usb_device_id usblp_ids [] = {
	{ USB_DEVICE_INFO(7, 1, 1) },
	{ USB_DEVICE_INFO(7, 1, 2) },
	{ USB_DEVICE_INFO(7, 1, 3) },
	{ USB_INTERFACE_INFO(7, 1, 1) },
	{ USB_INTERFACE_INFO(7, 1, 2) },
	{ USB_INTERFACE_INFO(7, 1, 3) },
	{ }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, usblp_ids);

static struct usb_driver usblp_driver = {
	owner:		THIS_MODULE,
	name:		"usblp",
	probe:		usblp_probe,
	disconnect:	usblp_disconnect,
	fops:		&usblp_fops,
	minor:		USBLP_MINOR_BASE,
	num_minors:	USBLP_MINORS,
	id_table:	usblp_ids,
};

static int __init usblp_init(void)
{
	if (usb_register(&usblp_driver))
		return -1;
	info(DRIVER_VERSION ": " DRIVER_DESC);
	return 0;
}

static void __exit usblp_exit(void)
{
	usb_deregister(&usblp_driver);
}

module_init(usblp_init);
module_exit(usblp_exit);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_PARM(proto_bias, "i");
MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
MODULE_LICENSE("GPL");