Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1439 insertions, 0 deletions

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
new file mode 100644
index 000000000..8dc4f5c49
--- /dev/null
+++ b/drivers/mtd/mtdchar.c
@@ -0,0 +1,1439 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
+ */
+
+#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"
+
+/*
+ * 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;
+
+	mtd = get_mtd_device(NULL, devnum);
+
+	if (IS_ERR(mtd))
+		return PTR_ERR(mtd);
+
+	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;
+	return 0;
+
+out1:
+	put_mtd_device(mtd);
+	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) {
+		if (*ppos < mtd->size)
+			count = mtd->size - *ppos;
+		else
+			count = 0;
+	}
+
+	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 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_info *master  = mtd_get_master(mtd);
+	struct mtd_file_info *mfi = file->private_data;
+	struct mtd_oob_ops ops = {};
+	uint32_t retlen;
+	int ret = 0;
+
+	if (length > 4096)
+		return -EINVAL;
+
+	if (!master->_write_oob)
+		return -EOPNOTSUPP;
+
+	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;
+
+	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 void adjust_oob_length(struct mtd_info *mtd, uint64_t start,
+			      struct mtd_oob_ops *ops)
+{
+	uint32_t start_page, end_page;
+	u32 oob_per_page;
+
+	if (ops->len == 0 || ops->ooblen == 0)
+		return;
+
+	start_page = mtd_div_by_ws(start, mtd);
+	end_page = mtd_div_by_ws(start + ops->len - 1, mtd);
+	oob_per_page = mtd_oobavail(mtd, ops);
+
+	ops->ooblen = min_t(size_t, ops->ooblen,
+			    (end_page - start_page + 1) * oob_per_page);
+}
+
+static noinline_for_stack int
+mtdchar_write_ioctl(struct mtd_info *mtd, struct mtd_write_req __user *argp)
+{
+	struct mtd_info *master = mtd_get_master(mtd);
+	struct mtd_write_req req;
+	const void __user *usr_data, *usr_oob;
+	uint8_t *datbuf = NULL, *oobbuf = NULL;
+	size_t datbuf_len, oobbuf_len;
+	int ret = 0;
+
+	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 (!master->_write_oob)
+		return -EOPNOTSUPP;
+
+	if (!usr_data)
+		req.len = 0;
+
+	if (!usr_oob)
+		req.ooblen = 0;
+
+	req.len &= 0xffffffff;
+	req.ooblen &= 0xffffffff;
+
+	if (req.start + req.len > mtd->size)
+		return -EINVAL;
+
+	datbuf_len = min_t(size_t, req.len, mtd->erasesize);
+	if (datbuf_len > 0) {
+		datbuf = kvmalloc(datbuf_len, GFP_KERNEL);
+		if (!datbuf)
+			return -ENOMEM;
+	}
+
+	oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
+	if (oobbuf_len > 0) {
+		oobbuf = kvmalloc(oobbuf_len, GFP_KERNEL);
+		if (!oobbuf) {
+			kvfree(datbuf);
+			return -ENOMEM;
+		}
+	}
+
+	while (req.len > 0 || (!usr_data && req.ooblen > 0)) {
+		struct mtd_oob_ops ops = {
+			.mode = req.mode,
+			.len = min_t(size_t, req.len, datbuf_len),
+			.ooblen = min_t(size_t, req.ooblen, oobbuf_len),
+			.datbuf = datbuf,
+			.oobbuf = oobbuf,
+		};
+
+		/*
+		 * Shorten non-page-aligned, eraseblock-sized writes so that
+		 * the write ends on an eraseblock boundary.  This is necessary
+		 * for adjust_oob_length() to properly handle non-page-aligned
+		 * writes.
+		 */
+		if (ops.len == mtd->erasesize)
+			ops.len -= mtd_mod_by_ws(req.start + ops.len, mtd);
+
+		/*
+		 * For writes which are not OOB-only, adjust the amount of OOB
+		 * data written according to the number of data pages written.
+		 * This is necessary to prevent OOB data from being skipped
+		 * over in data+OOB writes requiring multiple mtd_write_oob()
+		 * calls to be completed.
+		 */
+		adjust_oob_length(mtd, req.start, &ops);
+
+		if (copy_from_user(datbuf, usr_data, ops.len) ||
+		    copy_from_user(oobbuf, usr_oob, ops.ooblen)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		ret = mtd_write_oob(mtd, req.start, &ops);
+		if (ret)
+			break;
+
+		req.start += ops.retlen;
+		req.len -= ops.retlen;
+		usr_data += ops.retlen;
+
+		req.ooblen -= ops.oobretlen;
+		usr_oob += ops.oobretlen;
+	}
+
+	kvfree(datbuf);
+	kvfree(oobbuf);
+
+	return ret;
+}
+
+static noinline_for_stack int
+mtdchar_read_ioctl(struct mtd_info *mtd, struct mtd_read_req __user *argp)
+{
+	struct mtd_info *master = mtd_get_master(mtd);
+	struct mtd_read_req req;
+	void __user *usr_data, *usr_oob;
+	uint8_t *datbuf = NULL, *oobbuf = NULL;
+	size_t datbuf_len, oobbuf_len;
+	size_t orig_len, orig_ooblen;
+	int ret = 0;
+
+	if (copy_from_user(&req, argp, sizeof(req)))
+		return -EFAULT;
+
+	orig_len = req.len;
+	orig_ooblen = req.ooblen;
+
+	usr_data = (void __user *)(uintptr_t)req.usr_data;
+	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
+
+	if (!master->_read_oob)
+		return -EOPNOTSUPP;
+
+	if (!usr_data)
+		req.len = 0;
+
+	if (!usr_oob)
+		req.ooblen = 0;
+
+	req.ecc_stats.uncorrectable_errors = 0;
+	req.ecc_stats.corrected_bitflips = 0;
+	req.ecc_stats.max_bitflips = 0;
+
+	req.len &= 0xffffffff;
+	req.ooblen &= 0xffffffff;
+
+	if (req.start + req.len > mtd->size) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	datbuf_len = min_t(size_t, req.len, mtd->erasesize);
+	if (datbuf_len > 0) {
+		datbuf = kvmalloc(datbuf_len, GFP_KERNEL);
+		if (!datbuf) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
+	if (oobbuf_len > 0) {
+		oobbuf = kvmalloc(oobbuf_len, GFP_KERNEL);
+		if (!oobbuf) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	while (req.len > 0 || (!usr_data && req.ooblen > 0)) {
+		struct mtd_req_stats stats;
+		struct mtd_oob_ops ops = {
+			.mode = req.mode,
+			.len = min_t(size_t, req.len, datbuf_len),
+			.ooblen = min_t(size_t, req.ooblen, oobbuf_len),
+			.datbuf = datbuf,
+			.oobbuf = oobbuf,
+			.stats = &stats,
+		};
+
+		/*
+		 * Shorten non-page-aligned, eraseblock-sized reads so that the
+		 * read ends on an eraseblock boundary.  This is necessary in
+		 * order to prevent OOB data for some pages from being
+		 * duplicated in the output of non-page-aligned reads requiring
+		 * multiple mtd_read_oob() calls to be completed.
+		 */
+		if (ops.len == mtd->erasesize)
+			ops.len -= mtd_mod_by_ws(req.start + ops.len, mtd);
+
+		ret = mtd_read_oob(mtd, (loff_t)req.start, &ops);
+
+		req.ecc_stats.uncorrectable_errors +=
+			stats.uncorrectable_errors;
+		req.ecc_stats.corrected_bitflips += stats.corrected_bitflips;
+		req.ecc_stats.max_bitflips =
+			max(req.ecc_stats.max_bitflips, stats.max_bitflips);
+
+		if (ret && !mtd_is_bitflip_or_eccerr(ret))
+			break;
+
+		if (copy_to_user(usr_data, ops.datbuf, ops.retlen) ||
+		    copy_to_user(usr_oob, ops.oobbuf, ops.oobretlen)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		req.start += ops.retlen;
+		req.len -= ops.retlen;
+		usr_data += ops.retlen;
+
+		req.ooblen -= ops.oobretlen;
+		usr_oob += ops.oobretlen;
+	}
+
+	/*
+	 * As multiple iterations of the above loop (and therefore multiple
+	 * mtd_read_oob() calls) may be necessary to complete the read request,
+	 * adjust the final return code to ensure it accounts for all detected
+	 * ECC errors.
+	 */
+	if (!ret || mtd_is_bitflip(ret)) {
+		if (req.ecc_stats.uncorrectable_errors > 0)
+			ret = -EBADMSG;
+		else if (req.ecc_stats.corrected_bitflips > 0)
+			ret = -EUCLEAN;
+	}
+
+out:
+	req.len = orig_len - req.len;
+	req.ooblen = orig_ooblen - req.ooblen;
+
+	if (copy_to_user(argp, &req, sizeof(req)))
+		ret = -EFAULT;
+
+	kvfree(datbuf);
+	kvfree(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;
+	struct mtd_info *master = mtd_get_master(mtd);
+	void __user *argp = (void __user *)arg;
+	int ret = 0;
+	struct mtd_info_user info;
+
+	pr_debug("MTD_ioctl\n");
+
+	/*
+	 * Check the file mode to require "dangerous" commands to have write
+	 * permissions.
+	 */
+	switch (cmd) {
+	/* "safe" commands */
+	case MEMGETREGIONCOUNT:
+	case MEMGETREGIONINFO:
+	case MEMGETINFO:
+	case MEMREADOOB:
+	case MEMREADOOB64:
+	case MEMREAD:
+	case MEMISLOCKED:
+	case MEMGETOOBSEL:
+	case MEMGETBADBLOCK:
+	case OTPSELECT:
+	case OTPGETREGIONCOUNT:
+	case OTPGETREGIONINFO:
+	case ECCGETLAYOUT:
+	case ECCGETSTATS:
+	case MTDFILEMODE:
+	case BLKPG:
+	case BLKRRPART:
+		break;
+
+	/* "dangerous" commands */
+	case MEMERASE:
+	case MEMERASE64:
+	case MEMLOCK:
+	case MEMUNLOCK:
+	case MEMSETBADBLOCK:
+	case MEMWRITEOOB:
+	case MEMWRITEOOB64:
+	case MEMWRITE:
+	case OTPLOCK:
+	case OTPERASE:
+		if (!(file->f_mode & FMODE_WRITE))
+			return -EPERM;
+		break;
+
+	default:
+		return -ENOTTY;
+	}
+
+	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;
+
+		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
+		if (!erase)
+			ret = -ENOMEM;
+		else {
+			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;
+			}
+
+			ret = mtd_erase(mtd, erase);
+			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 MEMREAD:
+	{
+		ret = mtdchar_read_ioctl(mtd,
+		      (struct mtd_read_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 (!master->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);
+	}
+
+	case MEMSETBADBLOCK:
+	{
+		loff_t offs;
+
+		if (copy_from_user(&offs, argp, sizeof(loff_t)))
+			return -EFAULT;
+		return mtd_block_markbad(mtd, offs);
+	}
+
+	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:
+	case OTPERASE:
+	{
+		struct otp_info oinfo;
+
+		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
+			return -EINVAL;
+		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
+			return -EFAULT;
+		if (cmd == OTPLOCK)
+			ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
+		else
+			ret = mtd_erase_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 (!master->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;
+			break;
+
+		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;
+	}
+	}
+
+	return ret;
+} /* memory_ioctl */
+
+static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
+{
+	struct mtd_file_info *mfi = file->private_data;
+	struct mtd_info *mtd = mfi->mtd;
+	struct mtd_info *master = mtd_get_master(mtd);
+	int ret;
+
+	mutex_lock(&master->master.chrdev_lock);
+	ret = mtdchar_ioctl(file, cmd, arg);
+	mutex_unlock(&master->master.chrdev_lock);
+
+	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;
+	struct mtd_info *master = mtd_get_master(mtd);
+	void __user *argp = compat_ptr(arg);
+	int ret = 0;
+
+	mutex_lock(&master->master.chrdev_lock);
+
+	switch (cmd) {
+	case MEMWRITEOOB32:
+	{
+		struct mtd_oob_buf32 buf;
+		struct mtd_oob_buf32 __user *buf_user = argp;
+
+		if (!(file->f_mode & FMODE_WRITE)) {
+			ret = -EPERM;
+			break;
+		}
+
+		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(&master->master.chrdev_lock);
+
+	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);