misc.c

arm平台上的uclinux系统全部源代码

/*
 * linux/arch/arm/drivers/char/mouse.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 ([e-mail]) (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 <[e-mail]>
 *
 * Fixed a failing symbol register to free the device registration
 *		Alan Cox <[e-mail]> 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 <[e-mail]>,
 *  adapted by Bjorn Ekwall <[e-mail]>
 *  corrected by Alan Cox <[e-mail]>
 */

#include <linux/config.h>
#include <linux/module.h>

#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/malloc.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>

#include <linux/tty.h> /* needed by selection.h */
#include "vt_kern.h"
#include "selection.h" /* export its symbols */
#ifdef CONFIG_KERNELD
#include <linux/kerneld.h>
#endif

#include "mouse.h"

/*
 * Head entry for the doubly linked miscdevice list
 */
static struct miscdevice misc_list = { 0, "head", NULL, &misc_list, &misc_list };

/*
 * Assigned numbers, used for dynamic minors
 */
#define DYNAMIC_MINORS 64 /* like dynamic majors used to do */
static unsigned char misc_minors[DYNAMIC_MINORS / 8];

#ifndef MODULE
extern void watchdog_init(void);
extern int arch_mouse_init(void);
extern int con_get_info(int *mode, int *shift, int *col, int *row,
			struct tty_struct **tty);

#ifdef CONFIG_PROC_FS
static int proc_misc_read(char *buf, char **start, off_t offset, int len, int unused)
{
	struct miscdevice *p;

	len=0;
	for (p = misc_list.next; p != &misc_list; p = p->next)
		len += sprintf(buf+len, "%3i %s\n",p->minor, p->name ?: "");
	return len;
}

#endif /* PROC_FS */
#endif /* !MODULE */

static int misc_open(struct inode * inode, struct file * file)
{
	int minor = MINOR(inode->i_rdev);
	struct miscdevice *c = misc_list.next;
	file->f_op = NULL;

	while ((c != &misc_list) && (c->minor != minor))
		c = c->next;
	if (c == &misc_list) {
#ifdef CONFIG_KERNELD
		char modname[20];
		sprintf(modname, "char-major-%d-%d", MISC_MAJOR, minor);
		request_module(modname);
		c = misc_list.next;
		while ((c != &misc_list) && (c->minor != minor))
			c = c->next;
		if (c == &misc_list)
#endif
			return -ENODEV;
	}

	if ((file->f_op = c->fops))
		return file->f_op->open(inode,file);
	else
		return -ENODEV;
}

static struct file_operations misc_fops = {
        NULL,		/* seek */
	NULL,		/* read */
	NULL,		/* write */
	NULL,		/* readdir */
	NULL,		/* select */
	NULL,		/* ioctl */
	NULL,		/* mmap */
        misc_open,
        NULL		/* release */
};

int misc_register(struct miscdevice * misc)
{
	if (misc->next || misc->prev)
		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) return -EBUSY;
		misc->minor = i;
	}
	if (misc->minor < DYNAMIC_MINORS)
		misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
	MOD_INC_USE_COUNT;
	misc->next = &misc_list;
	misc->prev = misc_list.prev;
	misc->prev->next = misc;
	misc->next->prev = misc;
	return 0;
}

int misc_deregister(struct miscdevice * misc)
{
	int i = misc->minor;
	if (!misc->next || !misc->prev)
		return -EINVAL;
	MOD_DEC_USE_COUNT;
	misc->prev->next = misc->next;
	misc->next->prev = misc->prev;
	misc->next = NULL;
	misc->prev = NULL;
	if (i < DYNAMIC_MINORS && i>0) {
		misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
	}
	return 0;
}

#ifdef MODULE

#define misc_init init_module

void cleanup_module(void)
{
	unregister_chrdev(MISC_MAJOR, "misc");
}

#endif

static struct symbol_table misc_syms = {
/* Should this be surrounded with "#ifdef CONFIG_MODULES" ? */
#include <linux/symtab_begin.h>
	X(misc_register),
	X(misc_deregister),
#ifndef MODULE
	X(set_selection),   /* used by the kmouse module, can only */
	X(paste_selection), /* be exported if misc.c is in linked in */
	X(con_get_info),
#endif
#include <linux/symtab_end.h>
};

int misc_init(void)
{
#ifndef MODULE
#ifdef CONFIG_PROC_FS
	proc_register_dynamic(&proc_root, &(struct proc_dir_entry) {
		0, 4, "misc",
		S_IFREG | S_IRUGO, 1, 0, 0,
		0, NULL /* ops -- default to array */,
		&proc_misc_read /* get_info */,
	});	
#endif /* PROC_FS */
#ifdef CONFIG_MOUSE
	misc_mouse_init();
#endif
#ifdef CONFIG_SOFT_WATCHDOG
	watchdog_init();
#endif
#endif /* !MODULE */
	if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
	  printk("unable to get major %d for misc devices\n",
		 MISC_MAJOR);
		return -EIO;
	}

	if(register_symtab(&misc_syms)!=0)
	{
		unregister_chrdev(MISC_MAJOR, "misc");
		return -EIO;
	}
	return 0;
}