// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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 int port_num[LP_NO];

static unsigned int lp_count = 0;
static const struct class lp_class = {
        .name = "printer",
};

#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\n", minor);
                }
                error = -ENOSPC;
        } else if (!(status & LP_PSELECD)) {
                if (last != LP_PSELECD) {
                        last = LP_PSELECD;
                        printk(KERN_INFO "lp%d off-line\n", minor);
                }
                error = -EIO;
        } else if (!(status & LP_PERRORP)) {
                if (last != LP_PERRORP) {
                        last = LP_PERRORP;
                        printk(KERN_INFO "lp%d on fire\n", 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\n", 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\n", minor);
                        LP_F(minor) &= ~LP_BUSY;
                        ret = -ENOSPC;
                        goto out;
                } else if (!(status & LP_PSELECD)) {
                        printk(KERN_INFO "lp%d off-line\n", minor);
                        LP_F(minor) &= ~LP_BUSY;
                        ret = -EIO;
                        goto out;
                } else if (!(status & LP_PERRORP)) {
                        printk(KERN_ERR "lp%d printer error\n", 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\n", 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\n", 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;
                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, s64 tv_sec, long tv_usec)
{
        long to_jiffies;

        /* Convert to jiffies, place in lp_table */
        if (tv_sec < 0 || tv_usec < 0)
                return -EINVAL;

        /*
         * we used to not check, so let's not make this fatal,
         * but deal with user space passing a 32-bit tv_nsec in
         * a 64-bit field, capping the timeout to 1 second
         * worth of microseconds, and capping the total at
         * MAX_JIFFY_OFFSET.
         */
        if (tv_usec > 999999)
                tv_usec = 999999;

        if (tv_sec >= MAX_SEC_IN_JIFFIES - 1) {
                to_jiffies = MAX_JIFFY_OFFSET;
        } else {
                to_jiffies = DIV_ROUND_UP(tv_usec, 1000000/HZ);
                to_jiffies += tv_sec * (long) HZ;
        }

        if (to_jiffies <= 0) {
                return -EINVAL;
        }
        lp_table[minor].timeout = to_jiffies;
        return 0;
}

static int lp_set_timeout32(unsigned int minor, void __user *arg)
{
        s32 karg[2];

        if (copy_from_user(karg, arg, sizeof(karg)))
                return -EFAULT;

        return lp_set_timeout(minor, karg[0], karg[1]);
}

static int lp_set_timeout64(unsigned int minor, void __user *arg)
{
        s64 karg[2];

        if (copy_from_user(karg, arg, sizeof(karg)))
                return -EFAULT;

        /* sparc64 suseconds_t is 32-bit only */
        if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
                karg[1] >>= 32;

        return lp_set_timeout(minor, karg[0], karg[1]);
}

static long lp_ioctl(struct file *file, unsigned int cmd,
                        unsigned long arg)
{
        unsigned int minor;
        int ret;

        minor = iminor(file_inode(file));
        mutex_lock(&lp_mutex);
        switch (cmd) {
        case LPSETTIMEOUT_OLD:
                if (BITS_PER_LONG == 32) {
                        ret = lp_set_timeout32(minor, (void __user *)arg);
                        break;
                }
                fallthrough;    /* for 64-bit */
        case LPSETTIMEOUT_NEW:
                ret = lp_set_timeout64(minor, (void __user *)arg);
                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;
        int ret;

        minor = iminor(file_inode(file));
        mutex_lock(&lp_mutex);
        switch (cmd) {
        case LPSETTIMEOUT_OLD:
                if (!COMPAT_USE_64BIT_TIME) {
                        ret = lp_set_timeout32(minor, (void __user *)arg);
                        break;
                }
                fallthrough;    /* for x32 mode */
        case LPSETTIMEOUT_NEW:
                ret = lp_set_timeout64(minor, (void __user *)arg);
                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, '\n', 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\n";
                        int i = 2;

                        /* Dodge the original '\n', and put '\r\n' 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\n", 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.\n",
                               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.\n",
                               str);
        } else if (!strcmp(str, "reset")) {
                reset = true;
        }
        return 1;
}
#endif

static int lp_register(int nr, struct parport *port)
{
        struct pardev_cb ppdev_cb;

        memset(&ppdev_cb, 0, sizeof(ppdev_cb));
        ppdev_cb.preempt = lp_preempt;
        ppdev_cb.private = &lp_table[nr];
        lp_table[nr].dev = parport_register_dev_model(port, "lp",
                                                      &ppdev_cb, 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).\n", 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\n", CONSOLE_LP);
                } else
                        printk(KERN_ERR "lp%d: cannot run console on %s\n",
                               CONSOLE_LP, port->name);
        }
#endif
        port_num[nr] = port->number;

        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)\n",LP_NO);
                        return;
                }
                for (i = 0; i < LP_NO; i++)
                        if (port_num[i] == -1)
                                break;

                if (!lp_register(i, 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)
{
        int n;

        /* Write this some day. */
#ifdef CONFIG_LP_CONSOLE
        if (console_registered == port) {
                unregister_console(&lpcons);
                console_registered = NULL;
        }
#endif /* CONFIG_LP_CONSOLE */

        for (n = 0; n < LP_NO; n++) {
                if (port_num[n] == port->number) {
                        port_num[n] = -1;
                        lp_count--;
                        device_destroy(&lp_class, MKDEV(LP_MAJOR, n));
                        parport_unregister_device(lp_table[n].dev);
                }
        }
}

static struct parport_driver lp_driver = {
        .name = "lp",
        .match_port = lp_attach,
        .detach = lp_detach,
};

static int __init lp_init(void)
{
        int i, err;

        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;
                port_num[i] = -1;
        }

        if (register_chrdev(LP_MAJOR, "lp", &lp_fops)) {
                printk(KERN_ERR "lp: unable to get major %d\n", LP_MAJOR);
                return -EIO;
        }

        err = class_register(&lp_class);
        if (err)
                goto out_reg;

        if (parport_register_driver(&lp_driver)) {
                printk(KERN_ERR "lp: unable to register with parport\n");
                err = -EIO;
                goto out_class;
        }

        if (!lp_count) {
                printk(KERN_INFO "lp: driver loaded but no devices found\n");
#ifndef CONFIG_PARPORT_1284
                if (parport_nr[0] == LP_PARPORT_AUTO)
                        printk(KERN_INFO "lp: (is IEEE 1284 support enabled?)\n");
#endif
        }

        return 0;

out_class:
        class_unregister(&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'\n", parport[n]);
                                                return -ENODEV;
                                        }
                                }
                        }
                }
        }

        return lp_init();
}

static void lp_cleanup_module(void)
{
        parport_unregister_driver(&lp_driver);

#ifdef CONFIG_LP_CONSOLE
        unregister_console(&lpcons);
#endif

        unregister_chrdev(LP_MAJOR, "lp");
        class_unregister(&lp_class);
}

__setup("lp=", lp_setup);
module_init(lp_init_module);
module_exit(lp_cleanup_module);

MODULE_ALIAS_CHARDEV_MAJOR(LP_MAJOR);
MODULE_DESCRIPTION("Generic parallel printer driver");
MODULE_LICENSE("GPL");