/*
   * Generic parallel printer driver
   *
   * Copyright (C) 1992 by Jim Weigand and Linus Torvalds
   * Copyright (C) 1992,1993 by Michael K. Johnson
   * - Thanks much to Gunter Windau for pointing out to me where the error
   *   checking ought to be.
   * Copyright (C) 1993 by Nigel Gamble (added interrupt code)
   * Copyright (C) 1994 by Alan Cox (Modularised it)
   * LPCAREFUL, LPABORT, LPGETSTATUS added by Chris Metcalf, metcalf@lcs.mit.edu
   * Statistics and support for slow printers by Rob Janssen, rob@knoware.nl
   * "lp=" command line parameters added by Grant Guenther, grant@torque.net
   * lp_read (Status readback) support added by Carsten Gross,
   *                                             carsten@sol.wohnheim.uni-ulm.de
   * Support for parport by Philip Blundell <philb@gnu.org>
   * Parport sharing hacking by Andrea Arcangeli
   * Fixed kernel_(to/from)_user memory copy to check for errors
   * 				by Riccardo Facchetti <fizban@tin.it>
   * 22-JAN-1998  Added support for devfs  Richard Gooch <rgooch@atnf.csiro.au>
   * Redesigned interrupt handling for handle printers with buggy handshake
   *				by Andrea Arcangeli, 11 May 1998
   * Full efficient handling of printer with buggy irq handshake (now I have
   * understood the meaning of the strange handshake). This is done sending new
   * characters if the interrupt is just happened, even if the printer say to
   * be still BUSY. This is needed at least with Epson Stylus Color. To enable
   * the new TRUST_IRQ mode read the `LP OPTIMIZATION' section below...
   * Fixed the irq on the rising edge of the strobe case.
   * Obsoleted the CAREFUL flag since a printer that doesn' t work with
   * CAREFUL will block a bit after in lp_check_status().
   *				Andrea Arcangeli, 15 Oct 1998
   * Obsoleted and removed all the lowlevel stuff implemented in the last
   * month to use the IEEE1284 functions (that handle the _new_ compatibilty
   * mode fine).
   */
  
  /* This driver should, in theory, work with any parallel port that has an
   * appropriate low-level driver; all I/O is done through the parport
   * abstraction layer.
   *
   * If this driver is built into the kernel, you can configure it using the
   * kernel command-line.  For example:
   *
   *	lp=parport1,none,parport2	(bind lp0 to parport1, disable lp1 and
   *					 bind lp2 to parport2)
   *
   *	lp=auto				(assign lp devices to all ports that
   *				         have printers attached, as determined
   *					 by the IEEE-1284 autoprobe)
   * 
   *	lp=reset			(reset the printer during 
   *					 initialisation)
   *
   *	lp=off				(disable the printer driver entirely)
   *
   * If the driver is loaded as a module, similar functionality is available
   * using module parameters.  The equivalent of the above commands would be:
   *
   *	# insmod lp.o parport=1,none,2
   *
   *	# insmod lp.o parport=auto
   *
   *	# insmod lp.o reset=1
   */
  
  /* COMPATIBILITY WITH OLD KERNELS
   *
   * Under Linux 2.0 and previous versions, lp devices were bound to ports at
   * particular I/O addresses, as follows:
   *
   *	lp0		0x3bc
   *	lp1		0x378
   *	lp2		0x278
   *
   * The new driver, by default, binds lp devices to parport devices as it
   * finds them.  This means that if you only have one port, it will be bound
   * to lp0 regardless of its I/O address.  If you need the old behaviour, you
   * can force it using the parameters described above.
   */
  
  /*
   * The new interrupt handling code take care of the buggy handshake
   * of some HP and Epson printer:
   * ___
   * ACK    _______________    ___________
   *                       |__|
   * ____
   * BUSY   _________              _______
   *                 |____________|
   *
   * I discovered this using the printer scanner that you can find at:
   *
   *	ftp://e-mind.com/pub/linux/pscan/
   *
   *					11 May 98, Andrea Arcangeli
   *
   * My printer scanner run on an Epson Stylus Color show that such printer
   * generates the irq on the _rising_ edge of the STROBE. Now lp handle
   * this case fine too.
   *
   *					15 Oct 1998, Andrea Arcangeli
   *
   * The so called `buggy' handshake is really the well documented
   * compatibility mode IEEE1284 handshake. They changed the well known
   * Centronics handshake acking in the middle of busy expecting to not
   * break drivers or legacy application, while they broken linux lp
   * until I fixed it reverse engineering the protocol by hand some
   * month ago...
   *
   *                                     14 Dec 1998, Andrea Arcangeli
   *
   * Copyright (C) 2000 by Tim Waugh (added LPSETTIMEOUT ioctl)
   */
  
  #include <linux/module.h>
  #include <linux/init.h>

  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/major.h>

  #include <linux/sched/signal.h>

  #include <linux/slab.h>
  #include <linux/fcntl.h>
  #include <linux/delay.h>
  #include <linux/poll.h>
  #include <linux/console.h>
  #include <linux/device.h>
  #include <linux/wait.h>

  #include <linux/jiffies.h>

  #include <linux/mutex.h>

  #include <linux/compat.h>

  
  #include <linux/parport.h>
  #undef LP_STATS
  #include <linux/lp.h>
  
  #include <asm/irq.h>

  #include <linux/uaccess.h>

  
  /* if you have more than 8 printers, remember to increase LP_NO */
  #define LP_NO 8

  static DEFINE_MUTEX(lp_mutex);

  static struct lp_struct lp_table[LP_NO];
  
  static unsigned int lp_count = 0;

  static struct class *lp_class;

  
  #ifdef CONFIG_LP_CONSOLE

  static struct parport *console_registered;

  #endif /* CONFIG_LP_CONSOLE */
  
  #undef LP_DEBUG
  
  /* Bits used to manage claiming the parport device */
  #define LP_PREEMPT_REQUEST 1
  #define LP_PARPORT_CLAIMED 2
  
  /* --- low-level port access ----------------------------------- */
  
  #define r_dtr(x)	(parport_read_data(lp_table[(x)].dev->port))
  #define r_str(x)	(parport_read_status(lp_table[(x)].dev->port))
  #define w_ctr(x,y)	do { parport_write_control(lp_table[(x)].dev->port, (y)); } while (0)
  #define w_dtr(x,y)	do { parport_write_data(lp_table[(x)].dev->port, (y)); } while (0)
  
  /* Claim the parport or block trying unless we've already claimed it */
  static void lp_claim_parport_or_block(struct lp_struct *this_lp)
  {
  	if (!test_and_set_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
  		parport_claim_or_block (this_lp->dev);
  	}
  }
  
  /* Claim the parport or block trying unless we've already claimed it */
  static void lp_release_parport(struct lp_struct *this_lp)
  {
  	if (test_and_clear_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
  		parport_release (this_lp->dev);
  	}
  }
  
  
  
  static int lp_preempt(void *handle)
  {
  	struct lp_struct *this_lp = (struct lp_struct *)handle;
  	set_bit(LP_PREEMPT_REQUEST, &this_lp->bits);
  	return (1);
  }
  
  
  /* 
   * Try to negotiate to a new mode; if unsuccessful negotiate to
   * compatibility mode.  Return the mode we ended up in.
   */
  static int lp_negotiate(struct parport * port, int mode)
  {
  	if (parport_negotiate (port, mode) != 0) {
  		mode = IEEE1284_MODE_COMPAT;
  		parport_negotiate (port, mode);
  	}
  
  	return (mode);
  }
  
  static int lp_reset(int minor)
  {
  	int retval;
  	lp_claim_parport_or_block (&lp_table[minor]);
  	w_ctr(minor, LP_PSELECP);
  	udelay (LP_DELAY);
  	w_ctr(minor, LP_PSELECP | LP_PINITP);
  	retval = r_str(minor);
  	lp_release_parport (&lp_table[minor]);
  	return retval;
  }
  
  static void lp_error (int minor)
  {
  	DEFINE_WAIT(wait);
  	int polling;
  
  	if (LP_F(minor) & LP_ABORT)
  		return;
  
  	polling = lp_table[minor].dev->port->irq == PARPORT_IRQ_NONE;
  	if (polling) lp_release_parport (&lp_table[minor]);
  	prepare_to_wait(&lp_table[minor].waitq, &wait, TASK_INTERRUPTIBLE);
  	schedule_timeout(LP_TIMEOUT_POLLED);
  	finish_wait(&lp_table[minor].waitq, &wait);
  	if (polling) lp_claim_parport_or_block (&lp_table[minor]);
  	else parport_yield_blocking (lp_table[minor].dev);
  }
  
  static int lp_check_status(int minor)
  {
  	int error = 0;
  	unsigned int last = lp_table[minor].last_error;
  	unsigned char status = r_str(minor);
  	if ((status & LP_PERRORP) && !(LP_F(minor) & LP_CAREFUL))
  		/* No error. */
  		last = 0;
  	else if ((status & LP_POUTPA)) {
  		if (last != LP_POUTPA) {
  			last = LP_POUTPA;
  			printk(KERN_INFO "lp%d out of paper
  ", minor);
  		}
  		error = -ENOSPC;
  	} else if (!(status & LP_PSELECD)) {
  		if (last != LP_PSELECD) {
  			last = LP_PSELECD;
  			printk(KERN_INFO "lp%d off-line
  ", minor);
  		}
  		error = -EIO;
  	} else if (!(status & LP_PERRORP)) {
  		if (last != LP_PERRORP) {
  			last = LP_PERRORP;
  			printk(KERN_INFO "lp%d on fire
  ", minor);
  		}
  		error = -EIO;
  	} else {
  		last = 0; /* Come here if LP_CAREFUL is set and no
                               errors are reported. */
  	}
  
  	lp_table[minor].last_error = last;
  
  	if (last != 0)
  		lp_error(minor);
  
  	return error;
  }
  
  static int lp_wait_ready(int minor, int nonblock)
  {
  	int error = 0;
  
  	/* If we're not in compatibility mode, we're ready now! */
  	if (lp_table[minor].current_mode != IEEE1284_MODE_COMPAT) {
  	  return (0);
  	}
  
  	do {
  		error = lp_check_status (minor);
  		if (error && (nonblock || (LP_F(minor) & LP_ABORT)))
  			break;
  		if (signal_pending (current)) {
  			error = -EINTR;
  			break;
  		}
  	} while (error);
  	return error;
  }
  
  static ssize_t lp_write(struct file * file, const char __user * buf,
  		        size_t count, loff_t *ppos)
  {

  	unsigned int minor = iminor(file_inode(file));

  	struct parport *port = lp_table[minor].dev->port;
  	char *kbuf = lp_table[minor].lp_buffer;
  	ssize_t retv = 0;
  	ssize_t written;
  	size_t copy_size = count;
  	int nonblock = ((file->f_flags & O_NONBLOCK) ||
  			(LP_F(minor) & LP_ABORT));
  
  #ifdef LP_STATS

  	if (time_after(jiffies, lp_table[minor].lastcall + LP_TIME(minor)))

  		lp_table[minor].runchars = 0;
  
  	lp_table[minor].lastcall = jiffies;
  #endif
  
  	/* Need to copy the data from user-space. */
  	if (copy_size > LP_BUFFER_SIZE)
  		copy_size = LP_BUFFER_SIZE;

  	if (mutex_lock_interruptible(&lp_table[minor].port_mutex))

  		return -EINTR;
  
  	if (copy_from_user (kbuf, buf, copy_size)) {
  		retv = -EFAULT;
  		goto out_unlock;
  	}
  
   	/* Claim Parport or sleep until it becomes available
   	 */
  	lp_claim_parport_or_block (&lp_table[minor]);
  	/* Go to the proper mode. */
  	lp_table[minor].current_mode = lp_negotiate (port, 
  						     lp_table[minor].best_mode);
  
  	parport_set_timeout (lp_table[minor].dev,
  			     (nonblock ? PARPORT_INACTIVITY_O_NONBLOCK
  			      : lp_table[minor].timeout));
  
  	if ((retv = lp_wait_ready (minor, nonblock)) == 0)
  	do {
  		/* Write the data. */
  		written = parport_write (port, kbuf, copy_size);
  		if (written > 0) {
  			copy_size -= written;
  			count -= written;
  			buf  += written;
  			retv += written;
  		}
  
  		if (signal_pending (current)) {
  			if (retv == 0)
  				retv = -EINTR;
  
  			break;
  		}
  
  		if (copy_size > 0) {
  			/* incomplete write -> check error ! */
  			int error;
  
  			parport_negotiate (lp_table[minor].dev->port, 
  					   IEEE1284_MODE_COMPAT);
  			lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
  
  			error = lp_wait_ready (minor, nonblock);
  
  			if (error) {
  				if (retv == 0)
  					retv = error;
  				break;
  			} else if (nonblock) {
  				if (retv == 0)
  					retv = -EAGAIN;
  				break;
  			}
  
  			parport_yield_blocking (lp_table[minor].dev);
  			lp_table[minor].current_mode 
  			  = lp_negotiate (port, 
  					  lp_table[minor].best_mode);
  
  		} else if (need_resched())
  			schedule ();
  
  		if (count) {
  			copy_size = count;
  			if (copy_size > LP_BUFFER_SIZE)
  				copy_size = LP_BUFFER_SIZE;
  
  			if (copy_from_user(kbuf, buf, copy_size)) {
  				if (retv == 0)
  					retv = -EFAULT;
  				break;
  			}
  		}	
  	} while (count > 0);
  
  	if (test_and_clear_bit(LP_PREEMPT_REQUEST, 
  			       &lp_table[minor].bits)) {
  		printk(KERN_INFO "lp%d releasing parport
  ", minor);
  		parport_negotiate (lp_table[minor].dev->port, 
  				   IEEE1284_MODE_COMPAT);
  		lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
  		lp_release_parport (&lp_table[minor]);
  	}
  out_unlock:

  	mutex_unlock(&lp_table[minor].port_mutex);

  
   	return retv;
  }
  
  #ifdef CONFIG_PARPORT_1284
  
  /* Status readback conforming to ieee1284 */
  static ssize_t lp_read(struct file * file, char __user * buf,
  		       size_t count, loff_t *ppos)
  {
  	DEFINE_WAIT(wait);

  	unsigned int minor=iminor(file_inode(file));

  	struct parport *port = lp_table[minor].dev->port;
  	ssize_t retval = 0;
  	char *kbuf = lp_table[minor].lp_buffer;
  	int nonblock = ((file->f_flags & O_NONBLOCK) ||
  			(LP_F(minor) & LP_ABORT));
  
  	if (count > LP_BUFFER_SIZE)
  		count = LP_BUFFER_SIZE;

  	if (mutex_lock_interruptible(&lp_table[minor].port_mutex))

  		return -EINTR;
  
  	lp_claim_parport_or_block (&lp_table[minor]);
  
  	parport_set_timeout (lp_table[minor].dev,
  			     (nonblock ? PARPORT_INACTIVITY_O_NONBLOCK
  			      : lp_table[minor].timeout));
  
  	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
  	if (parport_negotiate (lp_table[minor].dev->port,
  			       IEEE1284_MODE_NIBBLE)) {
  		retval = -EIO;
  		goto out;
  	}
  
  	while (retval == 0) {
  		retval = parport_read (port, kbuf, count);
  
  		if (retval > 0)
  			break;
  
  		if (nonblock) {
  			retval = -EAGAIN;
  			break;
  		}
  
  		/* Wait for data. */
  
  		if (lp_table[minor].dev->port->irq == PARPORT_IRQ_NONE) {
  			parport_negotiate (lp_table[minor].dev->port,
  					   IEEE1284_MODE_COMPAT);
  			lp_error (minor);
  			if (parport_negotiate (lp_table[minor].dev->port,
  					       IEEE1284_MODE_NIBBLE)) {
  				retval = -EIO;
  				goto out;
  			}
  		} else {
  			prepare_to_wait(&lp_table[minor].waitq, &wait, TASK_INTERRUPTIBLE);
  			schedule_timeout(LP_TIMEOUT_POLLED);
  			finish_wait(&lp_table[minor].waitq, &wait);
  		}
  
  		if (signal_pending (current)) {
  			retval = -ERESTARTSYS;
  			break;
  		}
  
  		cond_resched ();
  	}
  	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
   out:
  	lp_release_parport (&lp_table[minor]);
  
  	if (retval > 0 && copy_to_user (buf, kbuf, retval))
  		retval = -EFAULT;

  	mutex_unlock(&lp_table[minor].port_mutex);

  
  	return retval;
  }
  
  #endif /* IEEE 1284 support */
  
  static int lp_open(struct inode * inode, struct file * file)
  {
  	unsigned int minor = iminor(inode);

  	int ret = 0;

  	mutex_lock(&lp_mutex);

  	if (minor >= LP_NO) {
  		ret = -ENXIO;
  		goto out;
  	}
  	if ((LP_F(minor) & LP_EXIST) == 0) {
  		ret = -ENXIO;
  		goto out;
  	}
  	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor))) {
  		ret = -EBUSY;
  		goto out;
  	}

  	/* If ABORTOPEN is set and the printer is offline or out of paper,
  	   we may still want to open it to perform ioctl()s.  Therefore we
  	   have commandeered O_NONBLOCK, even though it is being used in
  	   a non-standard manner.  This is strictly a Linux hack, and
  	   should most likely only ever be used by the tunelp application. */
  	if ((LP_F(minor) & LP_ABORTOPEN) && !(file->f_flags & O_NONBLOCK)) {
  		int status;
  		lp_claim_parport_or_block (&lp_table[minor]);
  		status = r_str(minor);
  		lp_release_parport (&lp_table[minor]);
  		if (status & LP_POUTPA) {
  			printk(KERN_INFO "lp%d out of paper
  ", minor);
  			LP_F(minor) &= ~LP_BUSY;

  			ret = -ENOSPC;
  			goto out;

  		} else if (!(status & LP_PSELECD)) {
  			printk(KERN_INFO "lp%d off-line
  ", minor);
  			LP_F(minor) &= ~LP_BUSY;

  			ret = -EIO;
  			goto out;

  		} else if (!(status & LP_PERRORP)) {
  			printk(KERN_ERR "lp%d printer error
  ", minor);
  			LP_F(minor) &= ~LP_BUSY;

  			ret = -EIO;
  			goto out;

  		}
  	}

  	lp_table[minor].lp_buffer = kmalloc(LP_BUFFER_SIZE, GFP_KERNEL);

  	if (!lp_table[minor].lp_buffer) {
  		LP_F(minor) &= ~LP_BUSY;

  		ret = -ENOMEM;
  		goto out;

  	}
  	/* Determine if the peripheral supports ECP mode */
  	lp_claim_parport_or_block (&lp_table[minor]);
  	if ( (lp_table[minor].dev->port->modes & PARPORT_MODE_ECP) &&
               !parport_negotiate (lp_table[minor].dev->port, 
                                   IEEE1284_MODE_ECP)) {
  		printk (KERN_INFO "lp%d: ECP mode
  ", minor);
  		lp_table[minor].best_mode = IEEE1284_MODE_ECP;
  	} else {
  		lp_table[minor].best_mode = IEEE1284_MODE_COMPAT;
  	}
  	/* Leave peripheral in compatibility mode */
  	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
  	lp_release_parport (&lp_table[minor]);
  	lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;

  out:

  	mutex_unlock(&lp_mutex);

  	return ret;

  }
  
  static int lp_release(struct inode * inode, struct file * file)
  {
  	unsigned int minor = iminor(inode);
  
  	lp_claim_parport_or_block (&lp_table[minor]);
  	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
  	lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
  	lp_release_parport (&lp_table[minor]);
  	kfree(lp_table[minor].lp_buffer);
  	lp_table[minor].lp_buffer = NULL;
  	LP_F(minor) &= ~LP_BUSY;
  	return 0;
  }

  static int lp_do_ioctl(unsigned int minor, unsigned int cmd,
  	unsigned long arg, void __user *argp)

  {

  	int status;
  	int retval = 0;

  
  #ifdef LP_DEBUG
  	printk(KERN_DEBUG "lp%d ioctl, cmd: 0x%x, arg: 0x%lx
  ", minor, cmd, arg);
  #endif
  	if (minor >= LP_NO)
  		return -ENODEV;
  	if ((LP_F(minor) & LP_EXIST) == 0)
  		return -ENODEV;
  	switch ( cmd ) {

  		case LPTIME:

  			if (arg > UINT_MAX / HZ)
  				return -EINVAL;

  			LP_TIME(minor) = arg * HZ/100;
  			break;
  		case LPCHAR:
  			LP_CHAR(minor) = arg;
  			break;
  		case LPABORT:
  			if (arg)
  				LP_F(minor) |= LP_ABORT;
  			else
  				LP_F(minor) &= ~LP_ABORT;
  			break;
  		case LPABORTOPEN:
  			if (arg)
  				LP_F(minor) |= LP_ABORTOPEN;
  			else
  				LP_F(minor) &= ~LP_ABORTOPEN;
  			break;
  		case LPCAREFUL:
  			if (arg)
  				LP_F(minor) |= LP_CAREFUL;
  			else
  				LP_F(minor) &= ~LP_CAREFUL;
  			break;
  		case LPWAIT:
  			LP_WAIT(minor) = arg;
  			break;
  		case LPSETIRQ: 
  			return -EINVAL;
  			break;
  		case LPGETIRQ:
  			if (copy_to_user(argp, &LP_IRQ(minor),
  					sizeof(int)))
  				return -EFAULT;
  			break;
  		case LPGETSTATUS:

  			if (mutex_lock_interruptible(&lp_table[minor].port_mutex))
  				return -EINTR;

  			lp_claim_parport_or_block (&lp_table[minor]);
  			status = r_str(minor);
  			lp_release_parport (&lp_table[minor]);

  			mutex_unlock(&lp_table[minor].port_mutex);

  
  			if (copy_to_user(argp, &status, sizeof(int)))
  				return -EFAULT;
  			break;
  		case LPRESET:
  			lp_reset(minor);
  			break;
  #ifdef LP_STATS
  		case LPGETSTATS:
  			if (copy_to_user(argp, &LP_STAT(minor),
  					sizeof(struct lp_stats)))
  				return -EFAULT;
  			if (capable(CAP_SYS_ADMIN))
  				memset(&LP_STAT(minor), 0,
  						sizeof(struct lp_stats));
  			break;
  #endif
   		case LPGETFLAGS:
   			status = LP_F(minor);
  			if (copy_to_user(argp, &status, sizeof(int)))
  				return -EFAULT;
  			break;

  		default:
  			retval = -EINVAL;
  	}
  	return retval;
  }

  static int lp_set_timeout(unsigned int minor, struct timeval *par_timeout)
  {
  	long to_jiffies;
  
  	/* Convert to jiffies, place in lp_table */
  	if ((par_timeout->tv_sec < 0) ||
  	    (par_timeout->tv_usec < 0)) {
  		return -EINVAL;
  	}
  	to_jiffies = DIV_ROUND_UP(par_timeout->tv_usec, 1000000/HZ);
  	to_jiffies += par_timeout->tv_sec * (long) HZ;
  	if (to_jiffies <= 0) {
  		return -EINVAL;
  	}
  	lp_table[minor].timeout = to_jiffies;
  	return 0;
  }
  
  static long lp_ioctl(struct file *file, unsigned int cmd,
  			unsigned long arg)
  {
  	unsigned int minor;
  	struct timeval par_timeout;
  	int ret;

  	minor = iminor(file_inode(file));

  	mutex_lock(&lp_mutex);

  	switch (cmd) {
  	case LPSETTIMEOUT:
  		if (copy_from_user(&par_timeout, (void __user *)arg,
  					sizeof (struct timeval))) {
  			ret = -EFAULT;
  			break;
  		}
  		ret = lp_set_timeout(minor, &par_timeout);
  		break;
  	default:
  		ret = lp_do_ioctl(minor, cmd, arg, (void __user *)arg);
  		break;
  	}

  	mutex_unlock(&lp_mutex);

  
  	return ret;
  }
  
  #ifdef CONFIG_COMPAT
  static long lp_compat_ioctl(struct file *file, unsigned int cmd,
  			unsigned long arg)
  {
  	unsigned int minor;
  	struct timeval par_timeout;

  	int ret;

  	minor = iminor(file_inode(file));

  	mutex_lock(&lp_mutex);

  	switch (cmd) {
  	case LPSETTIMEOUT:

  		if (compat_get_timeval(&par_timeout, compat_ptr(arg))) {

  			ret = -EFAULT;
  			break;
  		}
  		ret = lp_set_timeout(minor, &par_timeout);
  		break;
  #ifdef LP_STATS
  	case LPGETSTATS:
  		/* FIXME: add an implementation if you set LP_STATS */
  		ret = -EINVAL;
  		break;
  #endif
  	default:
  		ret = lp_do_ioctl(minor, cmd, arg, compat_ptr(arg));
  		break;
  	}

  	mutex_unlock(&lp_mutex);

  
  	return ret;
  }
  #endif

  static const struct file_operations lp_fops = {

  	.owner		= THIS_MODULE,
  	.write		= lp_write,

  	.unlocked_ioctl	= lp_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= lp_compat_ioctl,
  #endif

  	.open		= lp_open,
  	.release	= lp_release,
  #ifdef CONFIG_PARPORT_1284
  	.read		= lp_read,
  #endif

  	.llseek		= noop_llseek,

  };
  
  /* --- support for console on the line printer ----------------- */
  
  #ifdef CONFIG_LP_CONSOLE
  
  #define CONSOLE_LP 0
  
  /* If the printer is out of paper, we can either lose the messages or
   * stall until the printer is happy again.  Define CONSOLE_LP_STRICT
   * non-zero to get the latter behaviour. */
  #define CONSOLE_LP_STRICT 1
  
  /* The console must be locked when we get here. */
  
  static void lp_console_write (struct console *co, const char *s,
  			      unsigned count)
  {
  	struct pardevice *dev = lp_table[CONSOLE_LP].dev;
  	struct parport *port = dev->port;
  	ssize_t written;
  
  	if (parport_claim (dev))
  		/* Nothing we can do. */
  		return;
  
  	parport_set_timeout (dev, 0);
  
  	/* Go to compatibility mode. */
  	parport_negotiate (port, IEEE1284_MODE_COMPAT);
  
  	do {
  		/* Write the data, converting LF->CRLF as we go. */
  		ssize_t canwrite = count;
  		char *lf = memchr (s, '
  ', count);
  		if (lf)
  			canwrite = lf - s;
  
  		if (canwrite > 0) {
  			written = parport_write (port, s, canwrite);
  
  			if (written <= 0)
  				continue;
  
  			s += written;
  			count -= written;
  			canwrite -= written;
  		}
  
  		if (lf && canwrite <= 0) {
  			const char *crlf = "\r
  ";
  			int i = 2;
  
  			/* Dodge the original '
  ', and put '\r
  ' instead. */
  			s++;
  			count--;
  			do {
  				written = parport_write (port, crlf, i);
  				if (written > 0)
  					i -= written, crlf += written;
  			} while (i > 0 && (CONSOLE_LP_STRICT || written > 0));
  		}
  	} while (count > 0 && (CONSOLE_LP_STRICT || written > 0));
  
  	parport_release (dev);
  }
  
  static struct console lpcons = {
  	.name		= "lp",
  	.write		= lp_console_write,
  	.flags		= CON_PRINTBUFFER,
  };
  
  #endif /* console on line printer */
  
  /* --- initialisation code ------------------------------------- */
  
  static int parport_nr[LP_NO] = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };

  static char *parport[LP_NO];

  static bool reset;

  
  module_param_array(parport, charp, NULL, 0);
  module_param(reset, bool, 0);
  
  #ifndef MODULE
  static int __init lp_setup (char *str)
  {

  	static int parport_ptr;

  	int x;

  	if (get_option(&str, &x)) {

  		if (x == 0) {
  			/* disable driver on "lp=" or "lp=0" */
  			parport_nr[0] = LP_PARPORT_OFF;
  		} else {
  			printk(KERN_WARNING "warning: 'lp=0x%x' is deprecated, ignored
  ", x);
  			return 0;
  		}
  	} else if (!strncmp(str, "parport", 7)) {
  		int n = simple_strtoul(str+7, NULL, 10);
  		if (parport_ptr < LP_NO)
  			parport_nr[parport_ptr++] = n;
  		else
  			printk(KERN_INFO "lp: too many ports, %s ignored.
  ",
  			       str);
  	} else if (!strcmp(str, "auto")) {
  		parport_nr[0] = LP_PARPORT_AUTO;
  	} else if (!strcmp(str, "none")) {

  		if (parport_ptr < LP_NO)
  			parport_nr[parport_ptr++] = LP_PARPORT_NONE;
  		else
  			printk(KERN_INFO "lp: too many ports, %s ignored.
  ",
  			       str);

  	} else if (!strcmp(str, "reset")) {
  		reset = 1;
  	}
  	return 1;
  }
  #endif
  
  static int lp_register(int nr, struct parport *port)
  {
  	lp_table[nr].dev = parport_register_device(port, "lp", 
  						   lp_preempt, NULL, NULL, 0,
  						   (void *) &lp_table[nr]);
  	if (lp_table[nr].dev == NULL)
  		return 1;
  	lp_table[nr].flags |= LP_EXIST;
  
  	if (reset)
  		lp_reset(nr);

  	device_create(lp_class, port->dev, MKDEV(LP_MAJOR, nr), NULL,
  		      "lp%d", nr);

  
  	printk(KERN_INFO "lp%d: using %s (%s).
  ", nr, port->name, 
  	       (port->irq == PARPORT_IRQ_NONE)?"polling":"interrupt-driven");
  
  #ifdef CONFIG_LP_CONSOLE
  	if (!nr) {
  		if (port->modes & PARPORT_MODE_SAFEININT) {

  			register_console(&lpcons);

  			console_registered = port;
  			printk (KERN_INFO "lp%d: console ready
  ", CONSOLE_LP);
  		} else
  			printk (KERN_ERR "lp%d: cannot run console on %s
  ",
  				CONSOLE_LP, port->name);
  	}
  #endif
  
  	return 0;
  }
  
  static void lp_attach (struct parport *port)
  {
  	unsigned int i;

  	switch (parport_nr[0]) {

  	case LP_PARPORT_UNSPEC:
  	case LP_PARPORT_AUTO:
  		if (parport_nr[0] == LP_PARPORT_AUTO &&
  		    port->probe_info[0].class != PARPORT_CLASS_PRINTER)
  			return;
  		if (lp_count == LP_NO) {
  			printk(KERN_INFO "lp: ignoring parallel port (max. %d)
  ",LP_NO);
  			return;
  		}
  		if (!lp_register(lp_count, port))
  			lp_count++;
  		break;
  
  	default:
  		for (i = 0; i < LP_NO; i++) {
  			if (port->number == parport_nr[i]) {
  				if (!lp_register(i, port))
  					lp_count++;
  				break;
  			}
  		}
  		break;
  	}
  }
  
  static void lp_detach (struct parport *port)
  {
  	/* Write this some day. */
  #ifdef CONFIG_LP_CONSOLE
  	if (console_registered == port) {

  		unregister_console(&lpcons);

  		console_registered = NULL;
  	}
  #endif /* CONFIG_LP_CONSOLE */
  }
  
  static struct parport_driver lp_driver = {
  	.name = "lp",
  	.attach = lp_attach,
  	.detach = lp_detach,
  };
  
  static int __init lp_init (void)
  {
  	int i, err = 0;
  
  	if (parport_nr[0] == LP_PARPORT_OFF)
  		return 0;
  
  	for (i = 0; i < LP_NO; i++) {
  		lp_table[i].dev = NULL;
  		lp_table[i].flags = 0;
  		lp_table[i].chars = LP_INIT_CHAR;
  		lp_table[i].time = LP_INIT_TIME;
  		lp_table[i].wait = LP_INIT_WAIT;
  		lp_table[i].lp_buffer = NULL;
  #ifdef LP_STATS
  		lp_table[i].lastcall = 0;
  		lp_table[i].runchars = 0;
  		memset (&lp_table[i].stats, 0, sizeof (struct lp_stats));
  #endif
  		lp_table[i].last_error = 0;
  		init_waitqueue_head (&lp_table[i].waitq);
  		init_waitqueue_head (&lp_table[i].dataq);

  		mutex_init(&lp_table[i].port_mutex);

  		lp_table[i].timeout = 10 * HZ;
  	}
  
  	if (register_chrdev (LP_MAJOR, "lp", &lp_fops)) {
  		printk (KERN_ERR "lp: unable to get major %d
  ", LP_MAJOR);
  		return -EIO;
  	}

  	lp_class = class_create(THIS_MODULE, "printer");

  	if (IS_ERR(lp_class)) {
  		err = PTR_ERR(lp_class);

  		goto out_reg;

  	}
  
  	if (parport_register_driver (&lp_driver)) {
  		printk (KERN_ERR "lp: unable to register with parport
  ");
  		err = -EIO;
  		goto out_class;
  	}
  
  	if (!lp_count) {
  		printk (KERN_INFO "lp: driver loaded but no devices found
  ");
  #ifndef CONFIG_PARPORT_1284
  		if (parport_nr[0] == LP_PARPORT_AUTO)
  			printk (KERN_INFO "lp: (is IEEE 1284 support enabled?)
  ");
  #endif
  	}
  
  	return 0;
  
  out_class:

  	class_destroy(lp_class);

  out_reg:

  	unregister_chrdev(LP_MAJOR, "lp");
  	return err;
  }
  
  static int __init lp_init_module (void)
  {
  	if (parport[0]) {
  		/* The user gave some parameters.  Let's see what they were.  */
  		if (!strncmp(parport[0], "auto", 4))
  			parport_nr[0] = LP_PARPORT_AUTO;
  		else {
  			int n;
  			for (n = 0; n < LP_NO && parport[n]; n++) {
  				if (!strncmp(parport[n], "none", 4))
  					parport_nr[n] = LP_PARPORT_NONE;
  				else {
  					char *ep;
  					unsigned long r = simple_strtoul(parport[n], &ep, 0);
  					if (ep != parport[n]) 
  						parport_nr[n] = r;
  					else {
  						printk(KERN_ERR "lp: bad port specifier `%s'
  ", parport[n]);
  						return -ENODEV;
  					}
  				}
  			}
  		}
  	}
  
  	return lp_init();
  }
  
  static void lp_cleanup_module (void)
  {
  	unsigned int offset;
  
  	parport_unregister_driver (&lp_driver);
  
  #ifdef CONFIG_LP_CONSOLE
  	unregister_console (&lpcons);
  #endif
  
  	unregister_chrdev(LP_MAJOR, "lp");
  	for (offset = 0; offset < LP_NO; offset++) {
  		if (lp_table[offset].dev == NULL)
  			continue;
  		parport_unregister_device(lp_table[offset].dev);

  		device_destroy(lp_class, MKDEV(LP_MAJOR, offset));

  	}

  	class_destroy(lp_class);

  }
  
  __setup("lp=", lp_setup);
  module_init(lp_init_module);
  module_exit(lp_cleanup_module);
  
  MODULE_ALIAS_CHARDEV_MAJOR(LP_MAJOR);
  MODULE_LICENSE("GPL");