/*
 * 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/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/map.h>

#include <asm/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;
        struct inode *ino;
        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 count;
static struct vfsmount *mnt;
static struct file_system_type mtd_inodefs_type;

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;
        struct inode *mtd_ino;

        pr_debug("MTD_open\n");

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

        ret = simple_pin_fs(&mtd_inodefs_type, &mnt, &count);
        if (ret)
                return ret;

        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;
        }

        mtd_ino = iget_locked(mnt->mnt_sb, devnum);
        if (!mtd_ino) {
                ret = -ENOMEM;
                goto out1;
        }
        if (mtd_ino->i_state & I_NEW) {
                mtd_ino->i_private = mtd;
                mtd_ino->i_mode = S_IFCHR;
                mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
                unlock_new_inode(mtd_ino);
        }
        file->f_mapping = mtd_ino->i_mapping;

        /* 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 out2;
        }

        mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
        if (!mfi) {
                ret = -ENOMEM;
                goto out2;
        }
        mfi->ino = mtd_ino;
        mfi->mtd = mtd;
        file->private_data = mfi;
        mutex_unlock(&mtd_mutex);
        return 0;

out2:
        iput(mtd_ino);
out1:
        put_mtd_device(mtd);
out:
        mutex_unlock(&mtd_mutex);
        simple_release_fs(&mnt, &count);
        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);

        iput(mfi->ino);

        put_mtd_device(mtd);
        file->private_data = NULL;
        kfree(mfi);
        simple_release_fs(&mnt, &count);

        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);
                }
                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 occured 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) data from the larger struct,
 * nand_ecclayout, to the smaller, deprecated layout struct,
 * nand_ecclayout_user. This is necessary only to support the deprecated
 * API ioctl ECCGETLAYOUT while allowing all new functionality to use
 * nand_ecclayout flexibly (i.e. the struct may change size in new
 * releases without requiring major rewrites).
 */
static int shrink_ecclayout(const struct nand_ecclayout *from,
                struct nand_ecclayout_user *to)
{
        int i;

        if (!from || !to)
                return -EINVAL;

        memset(to, 0, sizeof(*to));

        to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
        for (i = 0; i < to->eccbytes; i++)
                to->eccpos[i] = from->eccpos[i];

        for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
                if (from->oobfree[i].length == 0 &&
                                from->oobfree[i].offset == 0)
                        break;
                to->oobavail += from->oobfree[i].length;
                to->oobfree[i] = from->oobfree[i];
        }

        return 0;
}

static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
                           struct blkpg_ioctl_arg __user *arg)
{
        struct blkpg_ioctl_arg a;
        struct blkpg_partition p;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
                return -EFAULT;

        if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
                return -EFAULT;

        switch (a.op) {
        case BLKPG_ADD_PARTITION:

                /* Only master mtd device must be used to add partitions */
                if (mtd_is_partition(mtd))
                        return -EINVAL;

                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;
        void __user *usr_data, *usr_oob;
        int ret;

        if (copy_from_user(&req, argp, sizeof(req)) ||
                        !access_ok(VERIFY_READ, req.usr_data, req.len) ||
                        !access_ok(VERIFY_READ, req.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;

        usr_data = (void __user *)(uintptr_t)req.usr_data;
        usr_oob = (void __user *)(uintptr_t)req.usr_oob;

        if (req.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 (req.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->ecclayout)
                        return -EOPNOTSUPP;
                if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
                        return -EINVAL;

                oi.useecc = MTD_NANDECC_AUTOPLACE;
                memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
                memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
                       sizeof(oi.oobfree));
                oi.eccbytes = mtd->ecclayout->eccbytes;

                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);
                if (!buf)
                        return -ENOMEM;
                switch (mfi->mode) {
                case MTD_FILE_MODE_OTP_FACTORY:
                        ret = mtd_get_fact_prot_info(mtd, buf, 4096);
                        break;
                case MTD_FILE_MODE_OTP_USER:
                        ret = mtd_get_user_prot_info(mtd, buf, 4096);
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }
                if (ret >= 0) {
                        if (cmd == OTPGETREGIONCOUNT) {
                                int nbr = ret / sizeof(struct otp_info);
                                ret = copy_to_user(argp, &nbr, sizeof(int));
                        } else
                                ret = copy_to_user(argp, buf, ret);
                        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->ecclayout)
                        return -EOPNOTSUPP;

                usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
                if (!usrlay)
                        return -ENOMEM;

                shrink_ecclayout(mtd->ecclayout, 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:
        {
                ret = mtdchar_blkpg_ioctl(mtd,
                      (struct blkpg_ioctl_arg __user *)arg);
                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;
        }
        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 ? -ENOSYS : ret;
}
#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 -ENOSYS;
#else
        return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
#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,
#endif
};

static const struct super_operations mtd_ops = {
        .drop_inode = generic_delete_inode,
        .statfs = simple_statfs,
};

static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
                                int flags, const char *dev_name, void *data)
{
        return mount_pseudo(fs_type, "mtd_inode:", &mtd_ops, NULL, MTD_INODE_FS_MAGIC);
}

static struct file_system_type mtd_inodefs_type = {
       .name = "mtd_inodefs",
       .mount = mtd_inodefs_mount,
       .kill_sb = kill_anon_super,
};
MODULE_ALIAS_FS("mtd_inodefs");

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;
        }

        ret = register_filesystem(&mtd_inodefs_type);
        if (ret) {
                pr_err("Can't register mtd_inodefs filesystem, error %d\n",
                       ret);
                goto err_unregister_chdev;
        }

        return ret;

err_unregister_chdev:
        __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
        return ret;
}

void __exit cleanup_mtdchar(void)
{
        unregister_filesystem(&mtd_inodefs_type);
        __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
}

MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);