scanner.c

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			for (cnt=0; cnt < cnt_max; cnt++) {
				printk("%X ", obuf[cnt]);
			}
			printk("\n");
		}
#endif
		if (partial != this_write) { /* Unable to write all contents of obuf */
			ret = -EIO;
			break;
		}

		if (partial) { /* Data written */
			buffer += partial;
			count -= partial;
			bytes_written += partial;
		} else { /* No data written */
			ret = 0;
			break;
		}
	}
	up(&(scn->gen_lock));
	mdelay(5);		/* This seems to help with SANE queries */
	return ret ? ret : bytes_written;
}

static ssize_t
read_scanner(struct file * file, char * buffer,
             size_t count, loff_t *ppos)
{
	struct scn_usb_data *scn;
	struct usb_device *dev;

	ssize_t bytes_read;	/* Overall count of bytes_read */
	ssize_t ret;

	kdev_t scn_minor;

	int partial;		/* Number of bytes successfully read */
	int this_read;		/* Max number of bytes to read */
	int result;
	int rd_expire = RD_EXPIRE;

	char *ibuf;

	scn = file->private_data;

	scn_minor = scn->scn_minor;

	ibuf = scn->ibuf;

	dev = scn->scn_dev;

	bytes_read = 0;
	ret = 0;

	file->f_dentry->d_inode->i_atime = CURRENT_TIME; /* Update the
                                                            atime of
                                                            the device
                                                            node */
	down(&(scn->gen_lock));

	while (count > 0) {
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}

		this_read = (count >= IBUF_SIZE) ? IBUF_SIZE : count;

		result = usb_bulk_msg(dev, usb_rcvbulkpipe(dev, scn->bulk_in_ep), ibuf, this_read, &partial, RD_NAK_TIMEOUT);
		dbg("read stats(%d): result:%d this_read:%d partial:%d count:%d", scn_minor, result, this_read, partial, count);

/*
 * Scanners are sometimes inheriently slow since they are mechanical
 * in nature.  USB bulk reads tend to timeout while the scanner is
 * positioning, resetting, warming up the lamp, etc if the timeout is
 * set too low.  A very long timeout parameter for bulk reads was used
 * to overcome this limitation, but this sometimes resulted in folks
 * having to wait for the timeout to expire after pressing Ctrl-C from
 * an application. The user was sometimes left with the impression
 * that something had hung or crashed when in fact the USB read was
 * just waiting on data.  So, the below code retains the same long
 * timeout period, but splits it up into smaller parts so that
 * Ctrl-C's are acted upon in a reasonable amount of time.
 */

		if (result == USB_ST_TIMEOUT && !partial) { /* Timeout
                                                               and no
                                                               data */
			if (--rd_expire <= 0) {
				warn("read_scanner(%d): excessive NAK's received", scn_minor);
				ret = -ETIME;
				break;
			} else {
				interruptible_sleep_on_timeout(&scn->rd_wait_q, RD_NAK_TIMEOUT);
				continue;
			}
		} else if ((result < 0) && (result != USB_ST_DATAUNDERRUN)) {
			warn("read_scanner(%d): funky result:%d. Please notify the maintainer.", scn_minor, (int)result);
			ret = -EIO;
			break;
		}

#ifdef RD_DATA_DUMP
		if (partial) {
			unsigned char cnt, cnt_max;
			cnt_max = (partial > 24) ? 24 : partial;
			printk(KERN_DEBUG "dump(%d): ", scn_minor);
			for (cnt=0; cnt < cnt_max; cnt++) {
				printk("%X ", ibuf[cnt]);
			}
			printk("\n");
		}
#endif

		if (partial) { /* Data returned */
			if (copy_to_user(buffer, ibuf, partial)) {
				ret = -EFAULT;
				break;
			}
			count -= this_read; /* Compensate for short reads */
			bytes_read += partial; /* Keep tally of what actually was read */
			buffer += partial;
		} else {
			ret = 0;
			break;
		}
	}
	up(&(scn->gen_lock));

	return ret ? ret : bytes_read;
}

static void *
probe_scanner(struct usb_device *dev, unsigned int ifnum,
	      const struct usb_device_id *id)
{
	struct scn_usb_data *scn;
	struct usb_interface_descriptor *interface;
	struct usb_endpoint_descriptor *endpoint;

	int ep_cnt;
	int ix;

	kdev_t scn_minor;

	char valid_device = 0;
	char have_bulk_in, have_bulk_out, have_intr;

	if (vendor != -1 && product != -1) {
		info("probe_scanner: User specified USB scanner -- Vendor:Product - %x:%x", vendor, product);
	}

	dbg("probe_scanner: USB dev address:%p", dev);
	dbg("probe_scanner: ifnum:%u", ifnum);

/*
 * 1. Check Vendor/Product
 * 2. Determine/Assign Bulk Endpoints
 * 3. Determine/Assign Intr Endpoint
 */

/*
 * There doesn't seem to be an imaging class defined in the USB
 * Spec. (yet).  If there is, HP isn't following it and it doesn't
 * look like anybody else is either.  Therefore, we have to test the
 * Vendor and Product ID's to see what we have.  Also, other scanners
 * may be able to use this driver by specifying both vendor and
 * product ID's as options to the scanner module in conf.modules.
 *
 * NOTE: Just because a product is supported here does not mean that
 * applications exist that support the product.  It's in the hopes
 * that this will allow developers a means to produce applications
 * that will support USB products.
 *
 * Until we detect a device which is pleasing, we silently punt.
 */

	for (ix = 0; ix < sizeof (scanner_device_ids) / sizeof (struct usb_device_id); ix++) {
		if ((dev->descriptor.idVendor == scanner_device_ids [ix].idVendor) &&
		    (dev->descriptor.idProduct == scanner_device_ids [ix].idProduct)) {
			valid_device = 1;
			break;
                }
	}
	if (dev->descriptor.idVendor == vendor &&   /* User specified */
	    dev->descriptor.idProduct == product) { /* User specified */
		valid_device = 1;
	}

        if (!valid_device)
                return NULL;    /* We didn't find anything pleasing */

/*
 * After this point we can be a little noisy about what we are trying to
 *  configure.
 */

	if (dev->descriptor.bNumConfigurations != 1) {
		info("probe_scanner: Only one device configuration is supported.");
		return NULL;
	}

	if (dev->config[0].bNumInterfaces != 1) {
		info("probe_scanner: Only one device interface is supported.");
		return NULL;
	}

	interface = dev->config[0].interface[ifnum].altsetting;
	endpoint = interface[ifnum].endpoint;

/*
 * Start checking for two bulk endpoints OR two bulk endpoints *and* one
 * interrupt endpoint. If we have an interrupt endpoint go ahead and
 * setup the handler. FIXME: This is a future enhancement...
 */

	dbg("probe_scanner: Number of Endpoints:%d", (int) interface->bNumEndpoints);

	if ((interface->bNumEndpoints != 2) && (interface->bNumEndpoints != 3)) {
		info("probe_scanner: Only two or three endpoints supported.");
		return NULL;
	}

	ep_cnt = have_bulk_in = have_bulk_out = have_intr = 0;

	while (ep_cnt < interface->bNumEndpoints) {

		if (!have_bulk_in && IS_EP_BULK_IN(endpoint[ep_cnt])) {
			ep_cnt++;
			have_bulk_in = ep_cnt;
			dbg("probe_scanner: bulk_in_ep:%d", have_bulk_in);
			continue;
		}

		if (!have_bulk_out && IS_EP_BULK_OUT(endpoint[ep_cnt])) {
			ep_cnt++;
			have_bulk_out = ep_cnt;
			dbg("probe_scanner: bulk_out_ep:%d", have_bulk_out);
			continue;
		}

		if (!have_intr && IS_EP_INTR(endpoint[ep_cnt])) {
			ep_cnt++;
			have_intr = ep_cnt;
			dbg("probe_scanner: intr_ep:%d", have_intr);
			continue;
		}
		info("probe_scanner: Undetected endpoint. Notify the maintainer.");
		return NULL;	/* Shouldn't ever get here unless we have something weird */
	}


/*
 * Perform a quick check to make sure that everything worked as it
 * should have.
 */

	switch(interface->bNumEndpoints) {
	case 2:
		if (!have_bulk_in || !have_bulk_out) {
			info("probe_scanner: Two bulk endpoints required.");
			return NULL;
		}
		break;
	case 3:
		if (!have_bulk_in || !have_bulk_out || !have_intr) {
			info("probe_scanner: Two bulk endpoints and one interrupt endpoint required.");
			return NULL;
		}
		break;
	default:
		info("probe_scanner: Endpoint determination failed.  Notify the maintainer.");
		return NULL;
	}


/*
 * Determine a minor number and initialize the structure associated
 * with it.  The problem with this is that we are counting on the fact
 * that the user will sequentially add device nodes for the scanner
 * devices.  */

	for (scn_minor = 0; scn_minor < SCN_MAX_MNR; scn_minor++) {
		if (!p_scn_table[scn_minor])
			break;
	}

/* Check to make sure that the last slot isn't already taken */
	if (p_scn_table[scn_minor]) {
		err("probe_scanner: No more minor devices remaining.");
		return NULL;
	}

	dbg("probe_scanner: Allocated minor:%d", scn_minor);

	if (!(scn = kmalloc (sizeof (struct scn_usb_data), GFP_KERNEL))) {
		err("probe_scanner: Out of memory.");
		return NULL;
	}
	memset (scn, 0, sizeof(struct scn_usb_data));
	dbg ("probe_scanner(%d): Address of scn:%p", scn_minor, scn);


/* Ok, if we detected an interrupt EP, setup a handler for it */
	if (have_intr) {
		dbg("probe_scanner(%d): Configuring IRQ handler for intr EP:%d", scn_minor, have_intr);
		FILL_INT_URB(&scn->scn_irq, dev,
			     usb_rcvintpipe(dev, have_intr),
			     &scn->button, 1, irq_scanner, scn,
			     // endpoint[(int)have_intr].bInterval);
			     250);

	        if (usb_submit_urb(&scn->scn_irq)) {
			err("probe_scanner(%d): Unable to allocate INT URB.", scn_minor);
                	kfree(scn);
                	return NULL;
        	}
	}


/* Ok, now initialize all the relevant values */
	if (!(scn->obuf = (char *)kmalloc(OBUF_SIZE, GFP_KERNEL))) {
		err("probe_scanner(%d): Not enough memory for the output buffer.", scn_minor);
		kfree(scn);
		return NULL;
	}
	dbg("probe_scanner(%d): obuf address:%p", scn_minor, scn->obuf);

	if (!(scn->ibuf = (char *)kmalloc(IBUF_SIZE, GFP_KERNEL))) {
		err("probe_scanner(%d): Not enough memory for the input buffer.", scn_minor);
		kfree(scn->obuf);
		kfree(scn);
		return NULL;
	}
	dbg("probe_scanner(%d): ibuf address:%p", scn_minor, scn->ibuf);

	scn->bulk_in_ep = have_bulk_in;
	scn->bulk_out_ep = have_bulk_out;
	scn->intr_ep = have_intr;
	scn->present = 1;
	scn->scn_dev = dev;
	scn->scn_minor = scn_minor;
	scn->isopen = 0;

	init_MUTEX(&(scn->gen_lock));

	return p_scn_table[scn_minor] = scn;
}

static void
disconnect_scanner(struct usb_device *dev, void *ptr)
{
	struct scn_usb_data *scn = (struct scn_usb_data *) ptr;

	if(scn->intr_ep) {
		dbg("disconnect_scanner(%d): Unlinking IRQ URB", scn->scn_minor);
		usb_unlink_urb(&scn->scn_irq);
	}
        usb_driver_release_interface(&scanner_driver,
                &scn->scn_dev->actconfig->interface[scn->ifnum]);

	kfree(scn->ibuf);
	kfree(scn->obuf);

	dbg("disconnect_scanner: De-allocating minor:%d", scn->scn_minor);
	p_scn_table[scn->scn_minor] = NULL;
	kfree (scn);
}

#ifdef SCN_IOCTL
static int
ioctl_scanner(struct inode *inode, struct file *file,
	      unsigned int cmd, unsigned long arg)
{
	struct usb_device *dev;

	int result;

	kdev_t scn_minor;

	scn_minor = USB_SCN_MINOR(inode);

	if (!p_scn_table[scn_minor]) {
		err("ioctl_scanner(%d): invalid scn_minor", scn_minor);
		return -ENODEV;
	}

	dev = p_scn_table[scn_minor]->scn_dev;

	switch (cmd)
	{
	case PV8630_IOCTL_INREQUEST :
	{
		struct {
			__u8  data;
			__u8  request;
			__u16 value;
			__u16 index;
		} args;

		if (copy_from_user(&args, (void *)arg, sizeof(args)))
			return -EFAULT;

		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
					 args.request, USB_TYPE_VENDOR|
					 USB_RECIP_DEVICE|USB_DIR_IN,
					 args.value, args.index, &args.data,
					 1, HZ*5);

		dbg("ioctl_scanner(%d): inreq: args.data:%x args.value:%x args.index:%x args.request:%x\n", scn_minor, args.data, args.value, args.index, args.request);

		if (copy_to_user((void *)arg, &args, sizeof(args)))
			return -EFAULT;

		dbg("ioctl_scanner(%d): inreq: result:%d\n", scn_minor, result);

		return result;
	}
	case PV8630_IOCTL_OUTREQUEST :
	{
		struct {
			__u8  request;
			__u16 value;
			__u16 index;
		} args;

		if (copy_from_user(&args, (void *)arg, sizeof(args)))
			return -EFAULT;

		dbg("ioctl_scanner(%d): outreq: args.value:%x args.index:%x args.request:%x\n", scn_minor, args.value, args.index, args.request);

		result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
					 args.request, USB_TYPE_VENDOR|
					 USB_RECIP_DEVICE|USB_DIR_OUT,
					 args.value, args.index, NULL,
					 0, HZ*5);

		dbg("ioctl_scanner(%d): outreq: result:%d\n", scn_minor, result);

		return result;
	}
	default:
		return -ENOIOCTLCMD;
	}
	return 0;
}
#endif /* SCN_IOCTL */

static struct
file_operations usb_scanner_fops = {
	read:		read_scanner,
	write:		write_scanner,
#ifdef SCN_IOCTL
	ioctl:		ioctl_scanner,
#endif /* SCN_IOCTL */
	open:		open_scanner,
	release:	close_scanner,
};

static struct
usb_driver scanner_driver = {
	name:		"usbscanner",
	probe:		probe_scanner,
	disconnect:	disconnect_scanner,
	fops:		&usb_scanner_fops,
	minor:		SCN_BASE_MNR,
	id_table:	NULL, /* This would be scanner_device_ids, but we
				 need to check every USB device, in case
				 we match a user defined vendor/product ID. */
};

void __exit
usb_scanner_exit(void)
{
	usb_deregister(&scanner_driver);
}

int __init
usb_scanner_init (void)
{
        if (usb_register(&scanner_driver) < 0)
                return -1;

	info("USB Scanner support registered.");
	return 0;
}

module_init(usb_scanner_init);
module_exit(usb_scanner_exit);