path: root/drivers/mtd/mtdchar.c

/*
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <linux/device.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/backing-dev.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/blkpg.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/map.h>

#include <asm/uaccess.h>

#define MTD_INODE_FS_MAGIC 0x11307854
static DEFINE_MUTEX(mtd_mutex);
static struct vfsmount *mtd_inode_mnt __read_mostly;

/*
 * Data structure to hold the pointer to the mtd device as well
 * as mode information ofr various use cases.
 */
struct mtd_file_info {
	struct mtd_info *mtd;
	struct inode *ino;
	enum mtd_file_modes mode;
};

static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
{
	struct mtd_file_info *mfi = file->private_data;
	struct mtd_info *mtd = mfi->mtd;

	switch (orig) {
	case SEEK_SET:
		break;
	case SEEK_CUR:
		offset += file->f_pos;
		break;
	case SEEK_END:
		offset += mtd->size;
		break;
	default:
		return -EINVAL;
	}

	if (offset >= 0 && offset <= mtd->size)
		return file->f_pos = offset;

	return -EINVAL;
}



static int mtd_open(struct inode *inode, struct file *file)
{
	int minor = iminor(inode);
	int devnum = minor >> 1;
	int ret = 0;
	struct mtd_info *mtd;
	struct mtd_file_info *mfi;
	struct inode *mtd_ino;

	DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");

	/* You can't open the RO devices RW */
	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
		return -EACCES;

	mutex_lock(&mtd_mutex);
	mtd = get_mtd_device(NULL, devnum);

	if (IS_ERR(mtd)) {
		ret = PTR_ERR(mtd);
		goto out;
	}

	if (mtd->type == MTD_ABSENT) {
		put_mtd_device(mtd);
		ret = -ENODEV;
		goto out;
	}

	mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
	if (!mtd_ino) {
		put_mtd_device(mtd);
		ret = -ENOMEM;
		goto out;
	}
	if (mtd_ino->i_state & I_NEW) {
		mtd_ino->i_private = mtd;
		mtd_ino->i_mode