text: /*
   * 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/magic.h>
  #include <linux/major.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
  #include <linux/mtd/map.h>
  
  #include <linux/uaccess.h>
  
  #include "mtdcore.h"
  
  static DEFINE_MUTEX(mtd_mutex);
  
  /*
   * Data structure to hold the pointer to the mtd device as well
   * as mode information of various use cases.
   */
  struct mtd_file_info {
  	struct mtd_info *mtd;
  	enum mtd_file_modes mode;
  };
  
  static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
  }
  
  static int mtdchar_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;
  
  	pr_debug("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) {
  		ret = -ENODEV;
  		goto out1;
  	}
  
  	/* You can't open it RW if it's not a writeable device */
  	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
  		ret = -EACCES;
  		goto out1;
  	}
  
  	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
  	if (!mfi) {
  		ret = -ENOMEM;
  		goto out1;
  	}
  	mfi->mtd = mtd;
  	file->private_data = mfi;
  	mutex_unlock(&mtd_mutex);
  	return 0;
  
  out1:
  	put_mtd_device(mtd);
  out:
  	mutex_unlock(&mtd_mutex);
  	return ret;
  } /* mtdchar_open */
  
  /*====================================================================*/
  
  static int mtdchar_close(struct inode *inode, struct file *file)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  
  	pr_debug("MTD_close\n");
  
  	/* Only sync if opened RW */
  	if ((file->f_mode & FMODE_WRITE))
  		mtd_sync(mtd);
  
  	put_mtd_device(mtd);
  	file->private_data = NULL;
  	kfree(mfi);
  
  	return 0;
  } /* mtdchar_close */
  
  /* Back in June 2001, dwmw2 wrote:
   *
   *   FIXME: This _really_ needs to die. In 2.5, we should lock the
   *   userspace buffer down and use it directly with readv/writev.
   *
   * The implementation below, using mtd_kmalloc_up_to, mitigates
   * allocation failures when the system is under low-memory situations
   * or if memory is highly fragmented at the cost of reducing the
   * performance of the requested transfer due to a smaller buffer size.
   *
   * A more complex but more memory-efficient implementation based on
   * get_user_pages and iovecs to cover extents of those pages is a
   * longer-term goal, as intimated by dwmw2 above. However, for the
   * write case, this requires yet more complex head and tail transfer
   * handling when those head and tail offsets and sizes are such that
   * alignment requirements are not met in the NAND subdriver.
   */
  
  static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
  			loff_t *ppos)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	size_t retlen;
  	size_t total_retlen=0;
  	int ret=0;
  	int len;
  	size_t size = count;
  	char *kbuf;
  
  	pr_debug("MTD_read\n");
  
  	if (*ppos + count > mtd->size)
  		count = mtd->size - *ppos;
  
  	if (!count)
  		return 0;
  
  	kbuf = mtd_kmalloc_up_to(mtd, &size);
  	if (!kbuf)
  		return -ENOMEM;
  
  	while (count) {
  		len = min_t(size_t, count, size);
  
  		switch (mfi->mode) {
  		case MTD_FILE_MODE_OTP_FACTORY:
  			ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
  						     &retlen, kbuf);
  			break;
  		case MTD_FILE_MODE_OTP_USER:
  			ret = mtd_read_user_prot_reg(mtd, *ppos, len,
  						     &retlen, kbuf);
  			break;
  		case MTD_FILE_MODE_RAW:
  		{
  			struct mtd_oob_ops ops;
  
  			ops.mode = MTD_OPS_RAW;
  			ops.datbuf = kbuf;
  			ops.oobbuf = NULL;
  			ops.len = len;
  
  			ret = mtd_read_oob(mtd, *ppos, &ops);
  			retlen = ops.retlen;
  			break;
  		}
  		default:
  			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
  		}
  		/* Nand returns -EBADMSG on ECC errors, but it returns
  		 * the data. For our userspace tools it is important
  		 * to dump areas with ECC errors!
  		 * For kernel internal usage it also might return -EUCLEAN
  		 * to signal the caller that a bitflip has occurred and has
  		 * been corrected by the ECC algorithm.
  		 * Userspace software which accesses NAND this way
  		 * must be aware of the fact that it deals with NAND
  		 */
  		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
  			*ppos += retlen;
  			if (copy_to_user(buf, kbuf, retlen)) {
  				kfree(kbuf);
  				return -EFAULT;
  			}
  			else
  				total_retlen += retlen;
  
  			count -= retlen;
  			buf += retlen;
  			if (retlen == 0)
  				count = 0;
  		}
  		else {
  			kfree(kbuf);
  			return ret;
  		}
  
  	}
  
  	kfree(kbuf);
  	return total_retlen;
  } /* mtdchar_read */
  
  static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
  			loff_t *ppos)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	size_t size = count;
  	char *kbuf;
  	size_t retlen;
  	size_t total_retlen=0;
  	int ret=0;
  	int len;
  
  	pr_debug("MTD_write\n");
  
  	if (*ppos == mtd->size)
  		return -ENOSPC;
  
  	if (*ppos + count > mtd->size)
  		count = mtd->size - *ppos;
  
  	if (!count)
  		return 0;
  
  	kbuf = mtd_kmalloc_up_to(mtd, &size);
  	if (!kbuf)
  		return -ENOMEM;
  
  	while (count) {
  		len = min_t(size_t, count, size);
  
  		if (copy_from_user(kbuf, buf, len)) {
  			kfree(kbuf);
  			return -EFAULT;
  		}
  
  		switch (mfi->mode) {
  		case MTD_FILE_MODE_OTP_FACTORY:
  			ret = -EROFS;
  			break;
  		case MTD_FILE_MODE_OTP_USER:
  			ret = mtd_write_user_prot_reg(mtd, *ppos, len,
  						      &retlen, kbuf);
  			break;
  
  		case MTD_FILE_MODE_RAW:
  		{
  			struct mtd_oob_ops ops;
  
  			ops.mode = MTD_OPS_RAW;
  			ops.datbuf = kbuf;
  			ops.oobbuf = NULL;
  			ops.ooboffs = 0;
  			ops.len = len;
  
  			ret = mtd_write_oob(mtd, *ppos, &ops);
  			retlen = ops.retlen;
  			break;
  		}
  
  		default:
  			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
  		}
  
  		/*
  		 * Return -ENOSPC only if no data could be written at all.
  		 * Otherwise just return the number of bytes that actually
  		 * have been written.
  		 */
  		if ((ret == -ENOSPC) && (total_retlen))
  			break;
  
  		if (!ret) {
  			*ppos += retlen;
  			total_retlen += retlen;
  			count -= retlen;
  			buf += retlen;
  		}
  		else {
  			kfree(kbuf);
  			return ret;
  		}
  	}
  
  	kfree(kbuf);
  	return total_retlen;
  } /* mtdchar_write */
  
  /*======================================================================
  
      IOCTL calls for getting device parameters.
  
  ======================================================================*/
  static void mtdchar_erase_callback (struct erase_info *instr)
  {
  	wake_up((wait_queue_head_t *)instr->priv);
  }
  
  static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
  {
  	struct mtd_info *mtd = mfi->mtd;
  	size_t retlen;
  
  	switch (mode) {
  	case MTD_OTP_FACTORY:
  		if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) ==
  				-EOPNOTSUPP)
  			return -EOPNOTSUPP;
  
  		mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
  		break;
  	case MTD_OTP_USER:
  		if (mtd_read_user_prot_reg(mtd, -1, 0, &retlen, NULL) ==
  				-EOPNOTSUPP)
  			return -EOPNOTSUPP;
  
  		mfi->mode = MTD_FILE_MODE_OTP_USER;
  		break;
  	case MTD_OTP_OFF:
  		mfi->mode = MTD_FILE_MODE_NORMAL;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
  	uint64_t start, uint32_t length, void __user *ptr,
  	uint32_t __user *retp)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_oob_ops ops;
  	uint32_t retlen;
  	int ret = 0;
  
  	if (!(file->f_mode & FMODE_WRITE))
  		return -EPERM;
  
  	if (length > 4096)
  		return -EINVAL;
  
  	if (!mtd->_write_oob)
  		ret = -EOPNOTSUPP;
  	else
  		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
  
  	if (ret)
  		return ret;
  
  	ops.ooblen = length;
  	ops.ooboffs = start & (mtd->writesize - 1);
  	ops.datbuf = NULL;
  	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
  		MTD_OPS_PLACE_OOB;
  
  	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
  		return -EINVAL;
  
  	ops.oobbuf = memdup_user(ptr, length);
  	if (IS_ERR(ops.oobbuf))
  		return PTR_ERR(ops.oobbuf);
  
  	start &= ~((uint64_t)mtd->writesize - 1);
  	ret = mtd_write_oob(mtd, start, &ops);
  
  	if (ops.oobretlen > 0xFFFFFFFFU)
  		ret = -EOVERFLOW;
  	retlen = ops.oobretlen;
  	if (copy_to_user(retp, &retlen, sizeof(length)))
  		ret = -EFAULT;
  
  	kfree(ops.oobbuf);
  	return ret;
  }
  
  static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
  	uint64_t start, uint32_t length, void __user *ptr,
  	uint32_t __user *retp)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_oob_ops ops;
  	int ret = 0;
  
  	if (length > 4096)
  		return -EINVAL;
  
  	if (!access_ok(VERIFY_WRITE, ptr, length))
  		return -EFAULT;
  
  	ops.ooblen = length;
  	ops.ooboffs = start & (mtd->writesize - 1);
  	ops.datbuf = NULL;
  	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
  		MTD_OPS_PLACE_OOB;
  
  	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
  		return -EINVAL;
  
  	ops.oobbuf = kmalloc(length, GFP_KERNEL);
  	if (!ops.oobbuf)
  		return -ENOMEM;
  
  	start &= ~((uint64_t)mtd->writesize - 1);
  	ret = mtd_read_oob(mtd, start, &ops);
  
  	if (put_user(ops.oobretlen, retp))
  		ret = -EFAULT;
  	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
  					    ops.oobretlen))
  		ret = -EFAULT;
  
  	kfree(ops.oobbuf);
  
  	/*
  	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
  	 * data. For our userspace tools it is important to dump areas
  	 * with ECC errors!
  	 * For kernel internal usage it also might return -EUCLEAN
  	 * to signal the caller that a bitflip has occurred and has
  	 * been corrected by the ECC algorithm.
  	 *
  	 * Note: currently the standard NAND function, nand_read_oob_std,
  	 * does not calculate ECC for the OOB area, so do not rely on
  	 * this behavior unless you have replaced it with your own.
  	 */
  	if (mtd_is_bitflip_or_eccerr(ret))
  		return 0;
  
  	return ret;
  }
  
  /*
   * Copies (and truncates, if necessary) OOB layout information to the
   * deprecated layout struct, nand_ecclayout_user. This is necessary only to
   * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
   * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
   * can describe any kind of OOB layout with almost zero overhead from a
   * memory usage point of view).
   */
  static int shrink_ecclayout(struct mtd_info *mtd,
  			    struct nand_ecclayout_user *to)
  {
  	struct mtd_oob_region oobregion;
  	int i, section = 0, ret;
  
  	if (!mtd || !to)
  		return -EINVAL;
  
  	memset(to, 0, sizeof(*to));
  
  	to->eccbytes = 0;
  	for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
  		u32 eccpos;
  
  		ret = mtd_ooblayout_ecc(mtd, section, &oobregion);
  		if (ret < 0) {
  			if (ret != -ERANGE)
  				return ret;
  
  			break;
  		}
  
  		eccpos = oobregion.offset;
  		for (; i < MTD_MAX_ECCPOS_ENTRIES &&
  		       eccpos < oobregion.offset + oobregion.length; i++) {
  			to->eccpos[i] = eccpos++;
  			to->eccbytes++;
  		}
  	}
  
  	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
  		ret = mtd_ooblayout_free(mtd, i, &oobregion);
  		if (ret < 0) {
  			if (ret != -ERANGE)
  				return ret;
  
  			break;
  		}
  
  		to->oobfree[i].offset = oobregion.offset;
  		to->oobfree[i].length = oobregion.length;
  		to->oobavail += to->oobfree[i].length;
  	}
  
  	return 0;
  }
  
  static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
  {
  	struct mtd_oob_region oobregion;
  	int i, section = 0, ret;
  
  	if (!mtd || !to)
  		return -EINVAL;
  
  	memset(to, 0, sizeof(*to));
  
  	to->eccbytes = 0;
  	for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
  		u32 eccpos;
  
  		ret = mtd_ooblayout_ecc(mtd, section, &oobregion);
  		if (ret < 0) {
  			if (ret != -ERANGE)
  				return ret;
  
  			break;
  		}
  
  		if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
  			return -EINVAL;
  
  		eccpos = oobregion.offset;
  		for (; eccpos < oobregion.offset + oobregion.length; i++) {
  			to->eccpos[i] = eccpos++;
  			to->eccbytes++;
  		}
  	}
  
  	for (i = 0; i < 8; i++) {
  		ret = mtd_ooblayout_free(mtd, i, &oobregion);
  		if (ret < 0) {
  			if (ret != -ERANGE)
  				return ret;
  
  			break;
  		}
  
  		to->oobfree[i][0] = oobregion.offset;
  		to->oobfree[i][1] = oobregion.length;
  	}
  
  	to->useecc = MTD_NANDECC_AUTOPLACE;
  
  	return 0;
  }
  
  static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
  			       struct blkpg_ioctl_arg *arg)
  {
  	struct blkpg_partition p;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;
  
  	if (copy_from_user(&p, arg->data, sizeof(p)))
  		return -EFAULT;
  
  	switch (arg->op) {
  	case BLKPG_ADD_PARTITION:
  
  		/* Only master mtd device must be used to add partitions */
  		if (mtd_is_partition(mtd))
  			return -EINVAL;
  
  		/* Sanitize user input */
  		p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
  
  		return mtd_add_partition(mtd, p.devname, p.start, p.length);
  
  	case BLKPG_DEL_PARTITION:
  
  		if (p.pno < 0)
  			return -EINVAL;
  
  		return mtd_del_partition(mtd, p.pno);
  
  	default:
  		return -EINVAL;
  	}
  }
  
  static int mtdchar_write_ioctl(struct mtd_info *mtd,
  		struct mtd_write_req __user *argp)
  {
  	struct mtd_write_req req;
  	struct mtd_oob_ops ops;
  	const void __user *usr_data, *usr_oob;
  	int ret;
  
  	if (copy_from_user(&req, argp, sizeof(req)))
  		return -EFAULT;
  
  	usr_data = (const void __user *)(uintptr_t)req.usr_data;
  	usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
  	if (!access_ok(VERIFY_READ, usr_data, req.len) ||
  	    !access_ok(VERIFY_READ, usr_oob, req.ooblen))
  		return -EFAULT;
  
  	if (!mtd->_write_oob)
  		return -EOPNOTSUPP;
  
  	ops.mode = req.mode;
  	ops.len = (size_t)req.len;
  	ops.ooblen = (size_t)req.ooblen;
  	ops.ooboffs = 0;
  
  	if (usr_data) {
  		ops.datbuf = memdup_user(usr_data, ops.len);
  		if (IS_ERR(ops.datbuf))
  			return PTR_ERR(ops.datbuf);
  	} else {
  		ops.datbuf = NULL;
  	}
  
  	if (usr_oob) {
  		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
  		if (IS_ERR(ops.oobbuf)) {
  			kfree(ops.datbuf);
  			return PTR_ERR(ops.oobbuf);
  		}
  	} else {
  		ops.oobbuf = NULL;
  	}
  
  	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
  
  	kfree(ops.datbuf);
  	kfree(ops.oobbuf);
  
  	return ret;
  }
  
  static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	void __user *argp = (void __user *)arg;
  	int ret = 0;
  	u_long size;
  	struct mtd_info_user info;
  
  	pr_debug("MTD_ioctl\n");
  
  	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
  	if (cmd & IOC_IN) {
  		if (!access_ok(VERIFY_READ, argp, size))
  			return -EFAULT;
  	}
  	if (cmd & IOC_OUT) {
  		if (!access_ok(VERIFY_WRITE, argp, size))
  			return -EFAULT;
  	}
  
  	switch (cmd) {
  	case MEMGETREGIONCOUNT:
  		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
  			return -EFAULT;
  		break;
  
  	case MEMGETREGIONINFO:
  	{
  		uint32_t ur_idx;
  		struct mtd_erase_region_info *kr;
  		struct region_info_user __user *ur = argp;
  
  		if (get_user(ur_idx, &(ur->regionindex)))
  			return -EFAULT;
  
  		if (ur_idx >= mtd->numeraseregions)
  			return -EINVAL;
  
  		kr = &(mtd->eraseregions[ur_idx]);
  
  		if (put_user(kr->offset, &(ur->offset))
  		    || put_user(kr->erasesize, &(ur->erasesize))
  		    || put_user(kr->numblocks, &(ur->numblocks)))
  			return -EFAULT;
  
  		break;
  	}
  
  	case MEMGETINFO:
  		memset(&info, 0, sizeof(info));
  		info.type	= mtd->type;
  		info.flags	= mtd->flags;
  		info.size	= mtd->size;
  		info.erasesize	= mtd->erasesize;
  		info.writesize	= mtd->writesize;
  		info.oobsize	= mtd->oobsize;
  		/* The below field is obsolete */
  		info.padding	= 0;
  		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
  			return -EFAULT;
  		break;
  
  	case MEMERASE:
  	case MEMERASE64:
  	{
  		struct erase_info *erase;
  
  		if(!(file->f_mode & FMODE_WRITE))
  			return -EPERM;
  
  		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
  		if (!erase)
  			ret = -ENOMEM;
  		else {
  			wait_queue_head_t waitq;
  			DECLARE_WAITQUEUE(wait, current);
  
  			init_waitqueue_head(&waitq);
  
  			if (cmd == MEMERASE64) {
  				struct erase_info_user64 einfo64;
  
  				if (copy_from_user(&einfo64, argp,
  					    sizeof(struct erase_info_user64))) {
  					kfree(erase);
  					return -EFAULT;
  				}
  				erase->addr = einfo64.start;
  				erase->len = einfo64.length;
  			} else {
  				struct erase_info_user einfo32;
  
  				if (copy_from_user(&einfo32, argp,
  					    sizeof(struct erase_info_user))) {
  					kfree(erase);
  					return -EFAULT;
  				}
  				erase->addr = einfo32.start;
  				erase->len = einfo32.length;
  			}
  			erase->mtd = mtd;
  			erase->callback = mtdchar_erase_callback;
  			erase->priv = (unsigned long)&waitq;
  
  			/*
  			  FIXME: Allow INTERRUPTIBLE. Which means
  			  not having the wait_queue head on the stack.
  
  			  If the wq_head is on the stack, and we
  			  leave because we got interrupted, then the
  			  wq_head is no longer there when the
  			  callback routine tries to wake us up.
  			*/
  			ret = mtd_erase(mtd, erase);
  			if (!ret) {
  				set_current_state(TASK_UNINTERRUPTIBLE);
  				add_wait_queue(&waitq, &wait);
  				if (erase->state != MTD_ERASE_DONE &&
  				    erase->state != MTD_ERASE_FAILED)
  					schedule();
  				remove_wait_queue(&waitq, &wait);
  				set_current_state(TASK_RUNNING);
  
  				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
  			}
  			kfree(erase);
  		}
  		break;
  	}
  
  	case MEMWRITEOOB:
  	{
  		struct mtd_oob_buf buf;
  		struct mtd_oob_buf __user *buf_user = argp;
  
  		/* NOTE: writes return length to buf_user->length */
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
  				buf.ptr, &buf_user->length);
  		break;
  	}
  
  	case MEMREADOOB:
  	{
  		struct mtd_oob_buf buf;
  		struct mtd_oob_buf __user *buf_user = argp;
  
  		/* NOTE: writes return length to buf_user->start */
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
  				buf.ptr, &buf_user->start);
  		break;
  	}
  
  	case MEMWRITEOOB64:
  	{
  		struct mtd_oob_buf64 buf;
  		struct mtd_oob_buf64 __user *buf_user = argp;
  
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
  				(void __user *)(uintptr_t)buf.usr_ptr,
  				&buf_user->length);
  		break;
  	}
  
  	case MEMREADOOB64:
  	{
  		struct mtd_oob_buf64 buf;
  		struct mtd_oob_buf64 __user *buf_user = argp;
  
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
  				(void __user *)(uintptr_t)buf.usr_ptr,
  				&buf_user->length);
  		break;
  	}
  
  	case MEMWRITE:
  	{
  		ret = mtdchar_write_ioctl(mtd,
  		      (struct mtd_write_req __user *)arg);
  		break;
  	}
  
  	case MEMLOCK:
  	{
  		struct erase_info_user einfo;
  
  		if (copy_from_user(&einfo, argp, sizeof(einfo)))
  			return -EFAULT;
  
  		ret = mtd_lock(mtd, einfo.start, einfo.length);
  		break;
  	}
  
  	case MEMUNLOCK:
  	{
  		struct erase_info_user einfo;
  
  		if (copy_from_user(&einfo, argp, sizeof(einfo)))
  			return -EFAULT;
  
  		ret = mtd_unlock(mtd, einfo.start, einfo.length);
  		break;
  	}
  
  	case MEMISLOCKED:
  	{
  		struct erase_info_user einfo;
  
  		if (copy_from_user(&einfo, argp, sizeof(einfo)))
  			return -EFAULT;
  
  		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
  		break;
  	}
  
  	/* Legacy interface */
  	case MEMGETOOBSEL:
  	{
  		struct nand_oobinfo oi;
  
  		if (!mtd->ooblayout)
  			return -EOPNOTSUPP;
  
  		ret = get_oobinfo(mtd, &oi);
  		if (ret)
  			return ret;
  
  		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
  			return -EFAULT;
  		break;
  	}
  
  	case MEMGETBADBLOCK:
  	{
  		loff_t offs;
  
  		if (copy_from_user(&offs, argp, sizeof(loff_t)))
  			return -EFAULT;
  		return mtd_block_isbad(mtd, offs);
  		break;
  	}
  
  	case MEMSETBADBLOCK:
  	{
  		loff_t offs;
  
  		if (copy_from_user(&offs, argp, sizeof(loff_t)))
  			return -EFAULT;
  		return mtd_block_markbad(mtd, offs);
  		break;
  	}
  
  	case OTPSELECT:
  	{
  		int mode;
  		if (copy_from_user(&mode, argp, sizeof(int)))
  			return -EFAULT;
  
  		mfi->mode = MTD_FILE_MODE_NORMAL;
  
  		ret = otp_select_filemode(mfi, mode);
  
  		file->f_pos = 0;
  		break;
  	}
  
  	case OTPGETREGIONCOUNT:
  	case OTPGETREGIONINFO:
  	{
  		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
  		size_t retlen;
  		if (!buf)
  			return -ENOMEM;
  		switch (mfi->mode) {
  		case MTD_FILE_MODE_OTP_FACTORY:
  			ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
  			break;
  		case MTD_FILE_MODE_OTP_USER:
  			ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
  			break;
  		default:
  			ret = -EINVAL;
  			break;
  		}
  		if (!ret) {
  			if (cmd == OTPGETREGIONCOUNT) {
  				int nbr = retlen / sizeof(struct otp_info);
  				ret = copy_to_user(argp, &nbr, sizeof(int));
  			} else
  				ret = copy_to_user(argp, buf, retlen);
  			if (ret)
  				ret = -EFAULT;
  		}
  		kfree(buf);
  		break;
  	}
  
  	case OTPLOCK:
  	{
  		struct otp_info oinfo;
  
  		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
  			return -EINVAL;
  		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
  			return -EFAULT;
  		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
  		break;
  	}
  
  	/* This ioctl is being deprecated - it truncates the ECC layout */
  	case ECCGETLAYOUT:
  	{
  		struct nand_ecclayout_user *usrlay;
  
  		if (!mtd->ooblayout)
  			return -EOPNOTSUPP;
  
  		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
  		if (!usrlay)
  			return -ENOMEM;
  
  		shrink_ecclayout(mtd, usrlay);
  
  		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
  			ret = -EFAULT;
  		kfree(usrlay);
  		break;
  	}
  
  	case ECCGETSTATS:
  	{
  		if (copy_to_user(argp, &mtd->ecc_stats,
  				 sizeof(struct mtd_ecc_stats)))
  			return -EFAULT;
  		break;
  	}
  
  	case MTDFILEMODE:
  	{
  		mfi->mode = 0;
  
  		switch(arg) {
  		case MTD_FILE_MODE_OTP_FACTORY:
  		case MTD_FILE_MODE_OTP_USER:
  			ret = otp_select_filemode(mfi, arg);
  			break;
  
  		case MTD_FILE_MODE_RAW:
  			if (!mtd_has_oob(mtd))
  				return -EOPNOTSUPP;
  			mfi->mode = arg;
  
  		case MTD_FILE_MODE_NORMAL:
  			break;
  		default:
  			ret = -EINVAL;
  		}
  		file->f_pos = 0;
  		break;
  	}
  
  	case BLKPG:
  	{
  		struct blkpg_ioctl_arg __user *blk_arg = argp;
  		struct blkpg_ioctl_arg a;
  
  		if (copy_from_user(&a, blk_arg, sizeof(a)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_blkpg_ioctl(mtd, &a);
  		break;
  	}
  
  	case BLKRRPART:
  	{
  		/* No reread partition feature. Just return ok */
  		ret = 0;
  		break;
  	}
  
  	default:
  		ret = -ENOTTY;
  	}
  
  	return ret;
  } /* memory_ioctl */
  
  static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
  {
  	int ret;
  
  	mutex_lock(&mtd_mutex);
  	ret = mtdchar_ioctl(file, cmd, arg);
  	mutex_unlock(&mtd_mutex);
  
  	return ret;
  }
  
  #ifdef CONFIG_COMPAT
  
  struct mtd_oob_buf32 {
  	u_int32_t start;
  	u_int32_t length;
  	compat_caddr_t ptr;	/* unsigned char* */
  };
  
  #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
  #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
  
  static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
  	unsigned long arg)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	void __user *argp = compat_ptr(arg);
  	int ret = 0;
  
  	mutex_lock(&mtd_mutex);
  
  	switch (cmd) {
  	case MEMWRITEOOB32:
  	{
  		struct mtd_oob_buf32 buf;
  		struct mtd_oob_buf32 __user *buf_user = argp;
  
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_writeoob(file, mtd, buf.start,
  				buf.length, compat_ptr(buf.ptr),
  				&buf_user->length);
  		break;
  	}
  
  	case MEMREADOOB32:
  	{
  		struct mtd_oob_buf32 buf;
  		struct mtd_oob_buf32 __user *buf_user = argp;
  
  		/* NOTE: writes return length to buf->start */
  		if (copy_from_user(&buf, argp, sizeof(buf)))
  			ret = -EFAULT;
  		else
  			ret = mtdchar_readoob(file, mtd, buf.start,
  				buf.length, compat_ptr(buf.ptr),
  				&buf_user->start);
  		break;
  	}
  
  	case BLKPG:
  	{
  		/* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
  		struct blkpg_compat_ioctl_arg __user *uarg = argp;
  		struct blkpg_compat_ioctl_arg compat_arg;
  		struct blkpg_ioctl_arg a;
  
  		if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
  			ret = -EFAULT;
  			break;
  		}
  
  		memset(&a, 0, sizeof(a));
  		a.op = compat_arg.op;
  		a.flags = compat_arg.flags;
  		a.datalen = compat_arg.datalen;
  		a.data = compat_ptr(compat_arg.data);
  
  		ret = mtdchar_blkpg_ioctl(mtd, &a);
  		break;
  	}
  
  	default:
  		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
  	}
  
  	mutex_unlock(&mtd_mutex);
  
  	return ret;
  }
  
  #endif /* CONFIG_COMPAT */
  
  /*
   * try to determine where a shared mapping can be made
   * - only supported for NOMMU at the moment (MMU can't doesn't copy private
   *   mappings)
   */
  #ifndef CONFIG_MMU
  static unsigned long mtdchar_get_unmapped_area(struct file *file,
  					   unsigned long addr,
  					   unsigned long len,
  					   unsigned long pgoff,
  					   unsigned long flags)
  {
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	unsigned long offset;
  	int ret;
  
  	if (addr != 0)
  		return (unsigned long) -EINVAL;
  
  	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
  		return (unsigned long) -EINVAL;
  
  	offset = pgoff << PAGE_SHIFT;
  	if (offset > mtd->size - len)
  		return (unsigned long) -EINVAL;
  
  	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
  	return ret == -EOPNOTSUPP ? -ENODEV : ret;
  }
  
  static unsigned mtdchar_mmap_capabilities(struct file *file)
  {
  	struct mtd_file_info *mfi = file->private_data;
  
  	return mtd_mmap_capabilities(mfi->mtd);
  }
  #endif
  
  /*
   * set up a mapping for shared memory segments
   */
  static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
  {
  #ifdef CONFIG_MMU
  	struct mtd_file_info *mfi = file->private_data;
  	struct mtd_info *mtd = mfi->mtd;
  	struct map_info *map = mtd->priv;
  
          /* This is broken because it assumes the MTD device is map-based
  	   and that mtd->priv is a valid struct map_info.  It should be
  	   replaced with something that uses the mtd_get_unmapped_area()
  	   operation properly. */
  	if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
  #ifdef pgprot_noncached
  		if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
  			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  #endif
  		return vm_iomap_memory(vma, map->phys, map->size);
  	}
  	return -ENODEV;
  #else
  	return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
  #endif
  }
  
  static const struct file_operations mtd_fops = {
  	.owner		= THIS_MODULE,
  	.llseek		= mtdchar_lseek,
  	.read		= mtdchar_read,
  	.write		= mtdchar_write,
  	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= mtdchar_compat_ioctl,
  #endif
  	.open		= mtdchar_open,
  	.release	= mtdchar_close,
  	.mmap		= mtdchar_mmap,
  #ifndef CONFIG_MMU
  	.get_unmapped_area = mtdchar_get_unmapped_area,
  	.mmap_capabilities = mtdchar_mmap_capabilities,
  #endif
  };
  
  int __init init_mtdchar(void)
  {
  	int ret;
  
  	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
  				   "mtd", &mtd_fops);
  	if (ret < 0) {
  		pr_err("Can't allocate major number %d for MTD\n",
  		       MTD_CHAR_MAJOR);
  		return ret;
  	}
  
  	return ret;
  }
  
  void __exit cleanup_mtdchar(void)
  {
  	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
  }
  
  MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
  