/*
 * linux/drivers/char/ppdev.c
 *
 * This is the code behind /dev/parport* -- it allows a user-space
 * application to use the parport subsystem.
 *
 * Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * A /dev/parportx device node represents an arbitrary device
 * on port 'x'.  The following operations are possible:
 *
 * open         do nothing, set up default IEEE 1284 protocol to be COMPAT
 * close        release port and unregister device (if necessary)
 * ioctl
 *   EXCL       register device exclusively (may fail)
 *   CLAIM      (register device first time) parport_claim_or_block
 *   RELEASE    parport_release
 *   SETMODE    set the IEEE 1284 protocol to use for read/write
 *   SETPHASE   set the IEEE 1284 phase of a particular mode.  Not to be
 *              confused with ioctl(fd, SETPHASER, &stun). ;-)
 *   DATADIR    data_forward / data_reverse
 *   WDATA      write_data
 *   RDATA      read_data
 *   WCONTROL   write_control
 *   RCONTROL   read_control
 *   FCONTROL   frob_control
 *   RSTATUS    read_status
 *   NEGOT      parport_negotiate
 *   YIELD      parport_yield_blocking
 *   WCTLONIRQ  on interrupt, set control lines
 *   CLRIRQ     clear (and return) interrupt count
 *   SETTIME    sets device timeout (struct timeval)
 *   GETTIME    gets device timeout (struct timeval)
 *   GETMODES   gets hardware supported modes (unsigned int)
 *   GETMODE    gets the current IEEE1284 mode
 *   GETPHASE   gets the current IEEE1284 phase
 *   GETFLAGS   gets current (user-visible) flags
 *   SETFLAGS   sets current (user-visible) flags
 * read/write   read or write in current IEEE 1284 protocol
 * select       wait for interrupt (in readfds)
 *
 * Changes:
 * Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
 *
 * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
 * - On error, copy_from_user and copy_to_user do not return -EFAULT,
 *   They return the positive number of bytes *not* copied due to address
 *   space errors.
 *
 * Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
 * Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/ioctl.h>
#include <linux/parport.h>
#include <linux/ctype.h>
#include <linux/poll.h>
#include <linux/major.h>
#include <linux/ppdev.h>
#include <linux/smp_lock.h>
#include <linux/uaccess.h>

#define PP_VERSION "ppdev: user-space parallel port driver"
#define CHRDEV "ppdev"

struct pp_struct {
        struct pardevice * pdev;
        wait_queue_head_t irq_wait;
        atomic_t irqc;
        unsigned int flags;
        int irqresponse;
        unsigned char irqctl;
        struct ieee1284_info state;
        struct ieee1284_info saved_state;
        long default_inactivity;
};

/* pp_struct.flags bitfields */
#define PP_CLAIMED    (1<<0)
#define PP_EXCL       (1<<1)

/* Other constants */
#define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
#define PP_BUFFER_SIZE 1024
#define PARDEVICE_MAX 8

/* ROUND_UP macro from fs/select.c */
#define ROUND_UP(x,y) (((x)+(y)-1)/(y))

static inline void pp_enable_irq (struct pp_struct *pp)
{
        struct parport *port = pp->pdev->port;
        port->ops->enable_irq (port);
}

static ssize_t pp_read (struct file * file, char __user * buf, size_t count,
                        loff_t * ppos)
{
        unsigned int minor = iminor(file->f_path.dentry->d_inode);
        struct pp_struct *pp = file->private_data;
        char * kbuffer;
        ssize_t bytes_read = 0;
        struct parport *pport;
        int mode;

        if (!(pp->flags & PP_CLAIMED)) {
                /* Don't have the port claimed */
                pr_debug(CHRDEV "%x: claim the port first\n", minor);
                return -EINVAL;
        }

        /* Trivial case. */
        if (count == 0)
                return 0;

        kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
        if (!kbuffer) {
                return -ENOMEM;
        }
        pport = pp->pdev->port;
        mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);

        parport_set_timeout (pp->pdev,
                             (file->f_flags & O_NONBLOCK) ?
                             PARPORT_INACTIVITY_O_NONBLOCK :
                             pp->default_inactivity);

        while (bytes_read == 0) {
                ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);

                if (mode == IEEE1284_MODE_EPP) {
                        /* various specials for EPP mode */
                        int flags = 0;
                        size_t (*fn)(struct parport *, void *, size_t, int);

                        if (pp->flags & PP_W91284PIC) {
                                flags |= PARPORT_W91284PIC;
                        }
                        if (pp->flags & PP_FASTREAD) {
                                flags |= PARPORT_EPP_FAST;
                        }
                        if (pport->ieee1284.mode & IEEE1284_ADDR) {
                                fn = pport->ops->epp_read_addr;
                        } else {
                                fn = pport->ops->epp_read_data;
                        }
                        bytes_read = (*fn)(pport, kbuffer, need, flags);
                } else {
                        bytes_read = parport_read (pport, kbuffer, need);
                }

                if (bytes_read != 0)
                        break;

                if (file->f_flags & O_NONBLOCK) {
                        bytes_read = -EAGAIN;
                        break;
                }

                if (signal_pending (current)) {
                        bytes_read = -ERESTARTSYS;
                        break;
                }

                cond_resched();
        }

        parport_set_timeout (pp->pdev, pp->default_inactivity);

        if (bytes_read > 0 && copy_to_user (buf, kbuffer, bytes_read))
                bytes_read = -EFAULT;

        kfree (kbuffer);
        pp_enable_irq (pp);
        return bytes_read;
}

static ssize_t pp_write (struct file * file, const char __user * buf,
                         size_t count, loff_t * ppos)
{
        unsigned int minor = iminor(file->f_path.dentry->d_inode);
        struct pp_struct *pp = file->private_data;
        char * kbuffer;
        ssize_t bytes_written = 0;
        ssize_t wrote;
        int mode;
        struct parport *pport;

        if (!(pp->flags & PP_CLAIMED)) {
                /* Don't have the port claimed */
                pr_debug(CHRDEV "%x: claim the port first\n", minor);
                return -EINVAL;
        }

        kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
        if (!kbuffer) {
                return -ENOMEM;
        }
        pport = pp->pdev->port;
        mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);

        parport_set_timeout (pp->pdev,
                             (file->f_flags & O_NONBLOCK) ?
                             PARPORT_INACTIVITY_O_NONBLOCK :
                             pp->default_inactivity);

        while (bytes_written < count) {
                ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);

                if (copy_from_user (kbuffer, buf + bytes_written, n)) {
                        bytes_written = -EFAULT;
                        break;
                }

                if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
                        /* do a fast EPP write */
                        if (pport->ieee1284.mode & IEEE1284_ADDR) {
                                wrote = pport->ops->epp_write_addr (pport,
                                        kbuffer, n, PARPORT_EPP_FAST);
                        } else {
                                wrote = pport->ops->epp_write_data (pport,
                                        kbuffer, n, PARPORT_EPP_FAST);
                        }
                } else {
                        wrote = parport_write (pp->pdev->port, kbuffer, n);
                }

                if (wrote <= 0) {
                        if (!bytes_written) {
                                bytes_written = wrote;
                        }
                        break;
                }

                bytes_written += wrote;

                if (file->f_flags & O_NONBLOCK) {
                        if (!bytes_written)
                                bytes_written = -EAGAIN;
                        break;
                }

                if (signal_pending (current)) {
                        if (!bytes_written) {
                                bytes_written = -EINTR;
                        }
                        break;
                }

                cond_resched();
        }

        parport_set_timeout (pp->pdev, pp->default_inactivity);

        kfree (kbuffer);
        pp_enable_irq (pp);
        return bytes_written;
}

static void pp_irq (void *private)
{
        struct pp_struct *pp = private;

        if (pp->irqresponse) {
                parport_write_control (pp->pdev->port, pp->irqctl);
                pp->irqresponse = 0;
        }

        atomic_inc (&pp->irqc);
        wake_up_interruptible (&pp->irq_wait);
}

static int register_device (int minor, struct pp_struct *pp)
{
        struct parport *port;
        struct pardevice * pdev = NULL;
        char *name;
        int fl;

        name = kmalloc (strlen (CHRDEV) + 3, GFP_KERNEL);
        if (name == NULL)
                return -ENOMEM;

        sprintf (name, CHRDEV "%x", minor);

        port = parport_find_number (minor);
        if (!port) {
                printk (KERN_WARNING "%s: no associated port!\n", name);
                kfree (name);
                return -ENXIO;
        }

        fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
        pdev = parport_register_device (port, name, NULL,
                                        NULL, pp_irq, fl, pp);
        parport_put_port (port);

        if (!pdev) {
                printk (KERN_WARNING "%s: failed to register device!\n", name);
                kfree (name);
                return -ENXIO;
        }

        pp->pdev = pdev;
        pr_debug("%s: registered pardevice\n", name);
        return 0;
}

static enum ieee1284_phase init_phase (int mode)
{
        switch (mode & ~(IEEE1284_DEVICEID
                         | IEEE1284_ADDR)) {
        case IEEE1284_MODE_NIBBLE:
        case IEEE1284_MODE_BYTE:
                return IEEE1284_PH_REV_IDLE;
        }
        return IEEE1284_PH_FWD_IDLE;
}

static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        unsigned int minor = iminor(file->f_path.dentry->d_inode);
        struct pp_struct *pp = file->private_data;
        struct parport * port;
        void __user *argp = (void __user *)arg;

        /* First handle the cases that don't take arguments. */
        switch (cmd) {
        case PPCLAIM:
            {
                struct ieee1284_info *info;
                int ret;

                if (pp->flags & PP_CLAIMED) {
                        pr_debug(CHRDEV "%x: you've already got it!\n", minor);
                        return -EINVAL;
                }

                /* Deferred device registration. */
                if (!pp->pdev) {
                        int err = register_device (minor, pp);
                        if (err) {
                                return err;
                        }
                }

                ret = parport_claim_or_block (pp->pdev);
                if (ret < 0)
                        return ret;

                pp->flags |= PP_CLAIMED;

                /* For interrupt-reporting to work, we need to be
                 * informed of each interrupt. */
                pp_enable_irq (pp);

                /* We may need to fix up the state machine. */
                info = &pp->pdev->port->ieee1284;
                pp->saved_state.mode = info->mode;
                pp->saved_state.phase = info->phase;
                info->mode = pp->state.mode;
                info->phase = pp->state.phase;
                pp->default_inactivity = parport_set_timeout (pp->pdev, 0);
                parport_set_timeout (pp->pdev, pp->default_inactivity);

                return 0;
            }
        case PPEXCL:
                if (pp->pdev) {
                        pr_debug(CHRDEV "%x: too late for PPEXCL; "
                                "already registered\n", minor);
                        if (pp->flags & PP_EXCL)
                                /* But it's not really an error. */
                                return 0;
                        /* There's no chance of making the driver happy. */
                        return -EINVAL;
                }

                /* Just remember to register the device exclusively
                 * when we finally do the registration. */
                pp->flags |= PP_EXCL;
                return 0;
        case PPSETMODE:
            {
                int mode;
                if (copy_from_user (&mode, argp, sizeof (mode)))
                        return -EFAULT;
                /* FIXME: validate mode */
                pp->state.mode = mode;
                pp->state.phase = init_phase (mode);

                if (pp->flags & PP_CLAIMED) {
                        pp->pdev->port->ieee1284.mode = mode;
                        pp->pdev->port->ieee1284.phase = pp->state.phase;
                }

                return 0;
            }
        case PPGETMODE:
            {
                int mode;

                if (pp->flags & PP_CLAIMED) {
                        mode = pp->pdev->port->ieee1284.mode;
                } else {
                        mode = pp->state.mode;
                }
                if (copy_to_user (argp, &mode, sizeof (mode))) {
                        return -EFAULT;
                }
                return 0;
            }
        case PPSETPHASE:
            {
                int phase;
                if (copy_from_user (&phase, argp, sizeof (phase))) {
                        return -EFAULT;
                }
                /* FIXME: validate phase */
                pp->state.phase = phase;

                if (pp->flags & PP_CLAIMED) {
                        pp->pdev->port->ieee1284.phase = phase;
                }

                return 0;
            }
        case PPGETPHASE:
            {
                int phase;

                if (pp->flags & PP_CLAIMED) {
                        phase = pp->pdev->port->ieee1284.phase;
                } else {
                        phase = pp->state.phase;
                }
                if (copy_to_user (argp, &phase, sizeof (phase))) {
                        return -EFAULT;
                }
                return 0;
            }
        case PPGETMODES:
            {
                unsigned int modes;

                port = parport_find_number (minor);
                if (!port)
                        return -ENODEV;

                modes = port->modes;
                if (copy_to_user (argp, &modes, sizeof (modes))) {
                        return -EFAULT;
                }
                return 0;
            }
        case PPSETFLAGS:
            {
                int uflags;

                if (copy_from_user (&uflags, argp, sizeof (uflags))) {
                        return -EFAULT;
                }
                pp->flags &= ~PP_FLAGMASK;
                pp->flags |= (uflags & PP_FLAGMASK);
                return 0;
            }
        case PPGETFLAGS:
            {
                int uflags;

                uflags = pp->flags & PP_FLAGMASK;
                if (copy_to_user (argp, &uflags, sizeof (uflags))) {
                        return -EFAULT;
                }
                return 0;
            }
        }       /* end switch() */

        /* Everything else requires the port to be claimed, so check
         * that now. */
        if ((pp->flags & PP_CLAIMED) == 0) {
                pr_debug(CHRDEV "%x: claim the port first\n", minor);
                return -EINVAL;
        }

        port = pp->pdev->port;
        switch (cmd) {
                struct ieee1284_info *info;
                unsigned char reg;
                unsigned char mask;
                int mode;
                int ret;
                struct timeval par_timeout;
                long to_jiffies;

        case PPRSTATUS:
                reg = parport_read_status (port);
                if (copy_to_user (argp, &reg, sizeof (reg)))
                        return -EFAULT;
                return 0;
        case PPRDATA:
                reg = parport_read_data (port);
                if (copy_to_user (argp, &reg, sizeof (reg)))
                        return -EFAULT;
                return 0;
        case PPRCONTROL:
                reg = parport_read_control (port);
                if (copy_to_user (argp, &reg, sizeof (reg)))
                        return -EFAULT;
                return 0;
        case PPYIELD:
                parport_yield_blocking (pp->pdev);
                return 0;

        case PPRELEASE:
                /* Save the state machine's state. */
                info = &pp->pdev->port->ieee1284;
                pp->state.mode = info->mode;
                pp->state.phase = info->phase;
                info->mode = pp->saved_state.mode;
                info->phase = pp->saved_state.phase;
                parport_release (pp->pdev);
                pp->flags &= ~PP_CLAIMED;
                return 0;

        case PPWCONTROL:
                if (copy_from_user (&reg, argp, sizeof (reg)))
                        return -EFAULT;
                parport_write_control (port, reg);
                return 0;

        case PPWDATA:
                if (copy_from_user (&reg, argp, sizeof (reg)))
                        return -EFAULT;
                parport_write_data (port, reg);
                return 0;

        case PPFCONTROL:
                if (copy_from_user (&mask, argp,
                                    sizeof (mask)))
                        return -EFAULT;
                if (copy_from_user (&reg, 1 + (unsigned char __user *) arg,
                                    sizeof (reg)))
                        return -EFAULT;
                parport_frob_control (port, mask, reg);
                return 0;

        case PPDATADIR:
                if (copy_from_user (&mode, argp, sizeof (mode)))
                        return -EFAULT;
                if (mode)
                        port->ops->data_reverse (port);
                else
                        port->ops->data_forward (port);
                return 0;

        case PPNEGOT:
                if (copy_from_user (&mode, argp, sizeof (mode)))
                        return -EFAULT;
                switch ((ret = parport_negotiate (port, mode))) {
                case 0: break;
                case -1: /* handshake failed, peripheral not IEEE 1284 */
                        ret = -EIO;
                        break;
                case 1:  /* handshake succeeded, peripheral rejected mode */
                        ret = -ENXIO;
                        break;
                }
                pp_enable_irq (pp);
                return ret;

        case PPWCTLONIRQ:
                if (copy_from_user (&reg, argp, sizeof (reg)))
                        return -EFAULT;

                /* Remember what to set the control lines to, for next
                 * time we get an interrupt. */
                pp->irqctl = reg;
                pp->irqresponse = 1;
                return 0;

        case PPCLRIRQ:
                ret = atomic_read (&pp->irqc);
                if (copy_to_user (argp, &ret, sizeof (ret)))
                        return -EFAULT;
                atomic_sub (ret, &pp->irqc);
                return 0;

        case PPSETTIME:
                if (copy_from_user (&par_timeout, argp, sizeof(struct timeval))) {
                        return -EFAULT;
                }
                /* Convert to jiffies, place in pp->pdev->timeout */
                if ((par_timeout.tv_sec < 0) || (par_timeout.tv_usec < 0)) {
                        return -EINVAL;
                }
                to_jiffies = ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
                to_jiffies += par_timeout.tv_sec * (long)HZ;
                if (to_jiffies <= 0) {
                        return -EINVAL;
                }
                pp->pdev->timeout = to_jiffies;
                return 0;

        case PPGETTIME:
                to_jiffies = pp->pdev->timeout;
                par_timeout.tv_sec = to_jiffies / HZ;
                par_timeout.tv_usec = (to_jiffies % (long)HZ) * (1000000/HZ);
                if (copy_to_user (argp, &par_timeout, sizeof(struct timeval)))
                        return -EFAULT;
                return 0;

        default:
                pr_debug(CHRDEV "%x: What? (cmd=0x%x)\n", minor, cmd);
                return -EINVAL;
        }

        /* Keep the compiler happy */
        return 0;
}

static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        long ret;
        lock_kernel();
        ret = pp_do_ioctl(file, cmd, arg);
        unlock_kernel();
        return ret;
}

static int pp_open (struct inode * inode, struct file * file)
{
        unsigned int minor = iminor(inode);
        struct pp_struct *pp;

        cycle_kernel_lock();
        if (minor >= PARPORT_MAX)
                return -ENXIO;

        pp = kmalloc (sizeof (struct pp_struct), GFP_KERNEL);
        if (!pp)
                return -ENOMEM;

        pp->state.mode = IEEE1284_MODE_COMPAT;
        pp->state.phase = init_phase (pp->state.mode);
        pp->flags = 0;
        pp->irqresponse = 0;
        atomic_set (&pp->irqc, 0);
        init_waitqueue_head (&pp->irq_wait);

        /* Defer the actual device registration until the first claim.
         * That way, we know whether or not the driver wants to have
         * exclusive access to the port (PPEXCL).
         */
        pp->pdev = NULL;
        file->private_data = pp;

        return 0;
}

static int pp_release (struct inode * inode, struct file * file)
{
        unsigned int minor = iminor(inode);
        struct pp_struct *pp = file->private_data;
        int compat_negot;

        compat_negot = 0;
        if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
            (pp->state.mode != IEEE1284_MODE_COMPAT)) {
                struct ieee1284_info *info;

                /* parport released, but not in compatibility mode */
                parport_claim_or_block (pp->pdev);
                pp->flags |= PP_CLAIMED;
                info = &pp->pdev->port->ieee1284;
                pp->saved_state.mode = info->mode;
                pp->saved_state.phase = info->phase;
                info->mode = pp->state.mode;
                info->phase = pp->state.phase;
                compat_negot = 1;
        } else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
            (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
                compat_negot = 2;
        }
        if (compat_negot) {
                parport_negotiate (pp->pdev->port, IEEE1284_MODE_COMPAT);
                pr_debug(CHRDEV "%x: negotiated back to compatibility "
                        "mode because user-space forgot\n", minor);
        }

        if (pp->flags & PP_CLAIMED) {
                struct ieee1284_info *info;

                info = &pp->pdev->port->ieee1284;
                pp->state.mode = info->mode;
                pp->state.phase = info->phase;
                info->mode = pp->saved_state.mode;
                info->phase = pp->saved_state.phase;
                parport_release (pp->pdev);
                if (compat_negot != 1) {
                        pr_debug(CHRDEV "%x: released pardevice "
                                "because user-space forgot\n", minor);
                }
        }

        if (pp->pdev) {
                const char *name = pp->pdev->name;
                parport_unregister_device (pp->pdev);
                kfree (name);
                pp->pdev = NULL;
                pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
        }

        kfree (pp);

        return 0;
}

/* No kernel lock held - fine */
static unsigned int pp_poll (struct file * file, poll_table * wait)
{
        struct pp_struct *pp = file->private_data;
        unsigned int mask = 0;

        poll_wait (file, &pp->irq_wait, wait);
        if (atomic_read (&pp->irqc))
                mask |= POLLIN | POLLRDNORM;

        return mask;
}

static struct class *ppdev_class;

static const struct file_operations pp_fops = {
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = pp_read,
        .write          = pp_write,
        .poll           = pp_poll,
        .unlocked_ioctl = pp_ioctl,
        .open           = pp_open,
        .release        = pp_release,
};

static void pp_attach(struct parport *port)
{
        device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
                      NULL, "parport%d", port->number);
}

static void pp_detach(struct parport *port)
{
        device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
}

static struct parport_driver pp_driver = {
        .name           = CHRDEV,
        .attach         = pp_attach,
        .detach         = pp_detach,
};

static int __init ppdev_init (void)
{
        int err = 0;

        if (register_chrdev (PP_MAJOR, CHRDEV, &pp_fops)) {
                printk (KERN_WARNING CHRDEV ": unable to get major %d\n",
                        PP_MAJOR);
                return -EIO;
        }
        ppdev_class = class_create(THIS_MODULE, CHRDEV);
        if (IS_ERR(ppdev_class)) {
                err = PTR_ERR(ppdev_class);
                goto out_chrdev;
        }
        if (parport_register_driver(&pp_driver)) {
                printk (KERN_WARNING CHRDEV ": unable to register with parport\n");
                goto out_class;
        }

        printk (KERN_INFO PP_VERSION "\n");
        goto out;

out_class:
        class_destroy(ppdev_class);
out_chrdev:
        unregister_chrdev(PP_MAJOR, CHRDEV);
out:
        return err;
}

static void __exit ppdev_cleanup (void)
{
        /* Clean up all parport stuff */
        parport_unregister_driver(&pp_driver);
        class_destroy(ppdev_class);
        unregister_chrdev (PP_MAJOR, CHRDEV);
}

module_init(ppdev_init);
module_exit(ppdev_cleanup);

MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);