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/*

 * linux/drivers/char/misc.c

 *

 * Generic misc open routine by Johan Myreen

 *

 * Based on code from Linus

 *

 * Teemu Rantanen's Microsoft Busmouse support and Derrick Cole's

 *   changes incorporated into 0.97pl4

 *   by Peter Cervasio (pete%q106fm.uucp@wupost.wustl.edu) (08SEP92)

 *   See busmouse.c for particulars.

 *

 * Made things a lot mode modular - easy to compile in just one or two

 * of the misc drivers, as they are now completely independent. Linus.

 *

 * Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk>

 *

 * Fixed a failing symbol register to free the device registration

 *              Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96

 *

 * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96

 *

 * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96

 *

 * Handling of mouse minor numbers for kerneld:

 *  Idea by Jacques Gelinas <jack@solucorp.qc.ca>,

 *  adapted by Bjorn Ekwall <bj0rn@blox.se>

 *  corrected by Alan Cox <alan@lxorguk.ukuu.org.uk>

 *

 * Changes for kmod (from kerneld):

 *      Cyrus Durgin <cider@speakeasy.org>

 *

 * Added devfs support. Richard Gooch <rgooch@atnf.csiro.au>  10-Jan-1998

 */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/fs.h>

#include <linux/errno.h>

#include <linux/miscdevice.h>

#include <linux/kernel.h>

#include <linux/major.h>

#include <linux/slab.h>

#include <linux/proc_fs.h>

#include <linux/devfs_fs_kernel.h>

#include <linux/stat.h>

#include <linux/init.h>

#include <linux/tty.h>

#include <linux/selection.h>

#include <linux/kmod.h>

#include "busmouse.h"

/*

 * Head entry for the doubly linked miscdevice list

 */

static struct miscdevice misc_list = { 0, "head", NULL, &misc_list, &misc_list };

static DECLARE_MUTEX(misc_sem);

/*

 * Assigned numbers, used for dynamic minors

 */

#define DYNAMIC_MINORS 64 /* like dynamic majors */

static unsigned char misc_minors[DYNAMIC_MINORS / 8];

extern int psaux_init(void);

extern int rtc_DP8570A_init(void);

extern int rtc_MK48T08_init(void);

extern int ds1286_init(void);

extern int pmu_device_init(void);

extern int tosh_init(void);

extern int i8k_init(void);

extern int lcd_init(void);

static int misc_read_proc(char *buf, char **start, off_t offset,

                          int len, int *eof, void *private)

{

        struct miscdevice *p;

        int written;

        written=0;

        for (p = misc_list.next; p != &misc_list && written < len; p = p->next) {

                written += sprintf(buf+written, "%3i %s\n",p->minor, p->name ?: "");

                if (written < offset) {

                        offset -= written;

                        written = 0;

                }

        }

        *start = buf + offset;

        written -= offset;

        if(written > len) {

                *eof = 0;

                return len;

        }

        *eof = 1;

        return (written<0) ? 0 : written;

}

static int misc_open(struct inode * inode, struct file * file)

{

        int minor = MINOR(inode->i_rdev);

        struct miscdevice *c;

        int err = -ENODEV;

        struct file_operations *old_fops, *new_fops = NULL;

        down(&misc_sem);

        c = misc_list.next;

        while ((c != &misc_list) && (c->minor != minor))

                c = c->next;

        if (c != &misc_list)

                new_fops = fops_get(c->fops);

        if (!new_fops) {

                char modname[20];

                up(&misc_sem);

                sprintf(modname, "char-major-%d-%d", MISC_MAJOR, minor);

                request_module(modname);

                down(&misc_sem);

                c = misc_list.next;

                while ((c != &misc_list) && (c->minor != minor))

                        c = c->next;

                if (c == &misc_list || (new_fops = fops_get(c->fops)) == NULL)

                        goto fail;

        }

        err = 0;

        old_fops = file->f_op;

        file->f_op = new_fops;

        if (file->f_op->open) {

                err=file->f_op->open(inode,file);

                if (err) {

                        fops_put(file->f_op);

                        file->f_op = fops_get(old_fops);

                }

        }

        fops_put(old_fops);

fail:

        up(&misc_sem);

        return err;

}

static struct file_operations misc_fops = {

        owner:          THIS_MODULE,

        open:           misc_open,

};

/**

 *      misc_register   -       register a miscellaneous device

 *      @misc: device structure

 *

 *      Register a miscellaneous device with the kernel. If the minor

 *      number is set to %MISC_DYNAMIC_MINOR a minor number is assigned

 *      and placed in the minor field of the structure. For other cases

 *      the minor number requested is used.

 *

 *      The structure passed is linked into the kernel and may not be

 *      destroyed until it has been unregistered.

 *

 *      A zero is returned on success and a negative errno code for

 *      failure.

 */

int misc_register(struct miscdevice * misc)

{

        static devfs_handle_t devfs_handle, dir;

        struct miscdevice *c;

        if (misc->next || misc->prev)

                return -EBUSY;

        down(&misc_sem);

        c = misc_list.next;

        while ((c != &misc_list) && (c->minor != misc->minor))

                c = c->next;

        if (c != &misc_list) {

                up(&misc_sem);

                return -EBUSY;

        }

        if (misc->minor == MISC_DYNAMIC_MINOR) {

                int i = DYNAMIC_MINORS;

                while (--i >= 0)

                        if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)

                                break;

                if (i<0)

                {

                        up(&misc_sem);

                        return -EBUSY;

                }

                misc->minor = i;

        }

        if (misc->minor < DYNAMIC_MINORS)

                misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);

        if (!devfs_handle)

                devfs_handle = devfs_mk_dir (NULL, "misc", NULL);

        dir = strchr (misc->name, '/') ? NULL : devfs_handle;

        misc->devfs_handle =

                devfs_register (dir, misc->name, DEVFS_FL_NONE,

                                MISC_MAJOR, misc->minor,

                                S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP,

                                misc->fops, NULL);

        /*

         * Add it to the front, so that later devices can "override"

         * earlier defaults

         */

        misc->prev = &misc_list;

        misc->next = misc_list.next;

        misc->prev->next = misc;

        misc->next->prev = misc;

        up(&misc_sem);

        return 0;

}

/**

 *      misc_deregister - unregister a miscellaneous device

 *      @misc: device to unregister

 *

 *      Unregister a miscellaneous device that was previously

 *      successfully registered with misc_register(). Success

 *      is indicated by a zero return, a negative errno code

 *      indicates an error.

 */

int misc_deregister(struct miscdevice * misc)

{

        int i = misc->minor;

        if (!misc->next || !misc->prev)

                return -EINVAL;

        down(&misc_sem);

        misc->prev->next = misc->next;

        misc->next->prev = misc->prev;

        misc->next = NULL;

        misc->prev = NULL;

        devfs_unregister (misc->devfs_handle);

        if (i < DYNAMIC_MINORS && i>0) {

                misc_minors[i>>3] &= ~(1 << (misc->minor & 7));

        }

        up(&misc_sem);

        return 0;

}

EXPORT_SYMBOL(misc_register);

EXPORT_SYMBOL(misc_deregister);

int __init misc_init(void)

{

        create_proc_read_entry("misc", 0, 0, misc_read_proc, NULL);

#ifdef CONFIG_MVME16x

        rtc_MK48T08_init();

#endif

#ifdef CONFIG_BVME6000

        rtc_DP8570A_init();

#endif

#ifdef CONFIG_SGI_DS1286

        ds1286_init();

#endif

#ifdef CONFIG_PMAC_PBOOK

        pmu_device_init();

#endif

#ifdef CONFIG_TOSHIBA

        tosh_init();

#endif

#ifdef CONFIG_COBALT_LCD

        lcd_init();

#endif

#ifdef CONFIG_I8K

        i8k_init();

#endif

        if (devfs_register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {

                printk("unable to get major %d for misc devices\n",

                       MISC_MAJOR);

                return -EIO;

        }

        return 0;

}