Linux 4.19.133

[linux/fpc-iii.git] / drivers / mtd / mtdpart.c

/*
 * Simple MTD partitioning layer
 *
 * Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
 * Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
 * Copyright © 2000-2010 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/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/kmod.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/err.h>
#include <linux/of.h>

#include "mtdcore.h"

/* Our partition linked list */
static LIST_HEAD(mtd_partitions);
static DEFINE_MUTEX(mtd_partitions_mutex);

/**
 * struct mtd_part - our partition node structure
 *
 * @mtd: struct holding partition details
 * @parent: parent mtd - flash device or another partition
 * @offset: partition offset relative to the *flash device*
 */
struct mtd_part {
        struct mtd_info mtd;
        struct mtd_info *parent;
        uint64_t offset;
        struct list_head list;
};

/*
 * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
 * the pointer to that structure.
 */
static inline struct mtd_part *mtd_to_part(const struct mtd_info *mtd)
{
        return container_of(mtd, struct mtd_part, mtd);
}


/*
 * MTD methods which simply translate the effective address and pass through
 * to the _real_ device.
 */

static int part_read(struct mtd_info *mtd, loff_t from, size_t len,
                size_t *retlen, u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        struct mtd_ecc_stats stats;
        int res;

        stats = part->parent->ecc_stats;
        res = part->parent->_read(part->parent, from + part->offset, len,
                                  retlen, buf);
        if (unlikely(mtd_is_eccerr(res)))
                mtd->ecc_stats.failed +=
                        part->parent->ecc_stats.failed - stats.failed;
        else
                mtd->ecc_stats.corrected +=
                        part->parent->ecc_stats.corrected - stats.corrected;
        return res;
}

static int part_point(struct mtd_info *mtd, loff_t from, size_t len,
                size_t *retlen, void **virt, resource_size_t *phys)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return part->parent->_point(part->parent, from + part->offset, len,
                                    retlen, virt, phys);
}

static int part_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return part->parent->_unpoint(part->parent, from + part->offset, len);
}

static int part_read_oob(struct mtd_info *mtd, loff_t from,
                struct mtd_oob_ops *ops)
{
        struct mtd_part *part = mtd_to_part(mtd);
        struct mtd_ecc_stats stats;
        int res;

        stats = part->parent->ecc_stats;
        res = part->parent->_read_oob(part->parent, from + part->offset, ops);
        if (unlikely(mtd_is_eccerr(res)))
                mtd->ecc_stats.failed +=
                        part->parent->ecc_stats.failed - stats.failed;
        else
                mtd->ecc_stats.corrected +=
                        part->parent->ecc_stats.corrected - stats.corrected;
        return res;
}

static int part_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
                size_t len, size_t *retlen, u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_read_user_prot_reg(part->parent, from, len,
                                                 retlen, buf);
}

static int part_get_user_prot_info(struct mtd_info *mtd, size_t len,
                                   size_t *retlen, struct otp_info *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_get_user_prot_info(part->parent, len, retlen,
                                                 buf);
}

static int part_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
                size_t len, size_t *retlen, u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_read_fact_prot_reg(part->parent, from, len,
                                                 retlen, buf);
}

static int part_get_fact_prot_info(struct mtd_info *mtd, size_t len,
                                   size_t *retlen, struct otp_info *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_get_fact_prot_info(part->parent, len, retlen,
                                                 buf);
}

static int part_write(struct mtd_info *mtd, loff_t to, size_t len,
                size_t *retlen, const u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_write(part->parent, to + part->offset, len,
                                    retlen, buf);
}

static int part_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
                size_t *retlen, const u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_panic_write(part->parent, to + part->offset, len,
                                          retlen, buf);
}

static int part_write_oob(struct mtd_info *mtd, loff_t to,
                struct mtd_oob_ops *ops)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return part->parent->_write_oob(part->parent, to + part->offset, ops);
}

static int part_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
                size_t len, size_t *retlen, u_char *buf)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_write_user_prot_reg(part->parent, from, len,
                                                  retlen, buf);
}

static int part_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
                size_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_lock_user_prot_reg(part->parent, from, len);
}

static int part_writev(struct mtd_info *mtd, const struct kvec *vecs,
                unsigned long count, loff_t to, size_t *retlen)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_writev(part->parent, vecs, count,
                                     to + part->offset, retlen);
}

static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
{
        struct mtd_part *part = mtd_to_part(mtd);
        int ret;

        instr->addr += part->offset;
        ret = part->parent->_erase(part->parent, instr);
        if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
                instr->fail_addr -= part->offset;
        instr->addr -= part->offset;

        return ret;
}

static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_lock(part->parent, ofs + part->offset, len);
}

static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_unlock(part->parent, ofs + part->offset, len);
}

static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_is_locked(part->parent, ofs + part->offset, len);
}

static void part_sync(struct mtd_info *mtd)
{
        struct mtd_part *part = mtd_to_part(mtd);
        part->parent->_sync(part->parent);
}

static int part_suspend(struct mtd_info *mtd)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_suspend(part->parent);
}

static void part_resume(struct mtd_info *mtd)
{
        struct mtd_part *part = mtd_to_part(mtd);
        part->parent->_resume(part->parent);
}

static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
{
        struct mtd_part *part = mtd_to_part(mtd);
        ofs += part->offset;
        return part->parent->_block_isreserved(part->parent, ofs);
}

static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
        struct mtd_part *part = mtd_to_part(mtd);
        ofs += part->offset;
        return part->parent->_block_isbad(part->parent, ofs);
}

static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        struct mtd_part *part = mtd_to_part(mtd);
        int res;

        ofs += part->offset;
        res = part->parent->_block_markbad(part->parent, ofs);
        if (!res)
                mtd->ecc_stats.badblocks++;
        return res;
}

static int part_get_device(struct mtd_info *mtd)
{
        struct mtd_part *part = mtd_to_part(mtd);
        return part->parent->_get_device(part->parent);
}

static void part_put_device(struct mtd_info *mtd)
{
        struct mtd_part *part = mtd_to_part(mtd);
        part->parent->_put_device(part->parent);
}

static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
                              struct mtd_oob_region *oobregion)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return mtd_ooblayout_ecc(part->parent, section, oobregion);
}

static int part_ooblayout_free(struct mtd_info *mtd, int section,
                               struct mtd_oob_region *oobregion)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return mtd_ooblayout_free(part->parent, section, oobregion);
}

static const struct mtd_ooblayout_ops part_ooblayout_ops = {
        .ecc = part_ooblayout_ecc,
        .free = part_ooblayout_free,
};

static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
{
        struct mtd_part *part = mtd_to_part(mtd);

        return part->parent->_max_bad_blocks(part->parent,
                                             ofs + part->offset, len);
}

static inline void free_partition(struct mtd_part *p)
{
        kfree(p->mtd.name);
        kfree(p);
}

static struct mtd_part *allocate_partition(struct mtd_info *parent,
                        const struct mtd_partition *part, int partno,
                        uint64_t cur_offset)
{
        int wr_alignment = (parent->flags & MTD_NO_ERASE) ? parent->writesize :
                                                            parent->erasesize;
        struct mtd_part *slave;
        u32 remainder;
        char *name;
        u64 tmp;

        /* allocate the partition structure */
        slave = kzalloc(sizeof(*slave), GFP_KERNEL);
        name = kstrdup(part->name, GFP_KERNEL);
        if (!name || !slave) {
                printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
                       parent->name);
                kfree(name);
                kfree(slave);
                return ERR_PTR(-ENOMEM);
        }

        /* set up the MTD object for this partition */
        slave->mtd.type = parent->type;
        slave->mtd.flags = parent->flags & ~part->mask_flags;
        slave->mtd.size = part->size;
        slave->mtd.writesize = parent->writesize;
        slave->mtd.writebufsize = parent->writebufsize;
        slave->mtd.oobsize = parent->oobsize;
        slave->mtd.oobavail = parent->oobavail;
        slave->mtd.subpage_sft = parent->subpage_sft;
        slave->mtd.pairing = parent->pairing;

        slave->mtd.name = name;
        slave->mtd.owner = parent->owner;

        /* NOTE: Historically, we didn't arrange MTDs as a tree out of
         * concern for showing the same data in multiple partitions.
         * However, it is very useful to have the master node present,
         * so the MTD_PARTITIONED_MASTER option allows that. The master
         * will have device nodes etc only if this is set, so make the
         * parent conditional on that option. Note, this is a way to
         * distinguish between the master and the partition in sysfs.
         */
        slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd_is_partition(parent) ?
                                &parent->dev :
                                parent->dev.parent;
        slave->mtd.dev.of_node = part->of_node;

        if (parent->_read)
                slave->mtd._read = part_read;
        if (parent->_write)
                slave->mtd._write = part_write;

        if (parent->_panic_write)
                slave->mtd._panic_write = part_panic_write;

        if (parent->_point && parent->_unpoint) {
                slave->mtd._point = part_point;
                slave->mtd._unpoint = part_unpoint;
        }

        if (parent->_read_oob)
                slave->mtd._read_oob = part_read_oob;
        if (parent->_write_oob)
                slave->mtd._write_oob = part_write_oob;
        if (parent->_read_user_prot_reg)
                slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
        if (parent->_read_fact_prot_reg)
                slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
        if (parent->_write_user_prot_reg)
                slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
        if (parent->_lock_user_prot_reg)
                slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
        if (parent->_get_user_prot_info)
                slave->mtd._get_user_prot_info = part_get_user_prot_info;
        if (parent->_get_fact_prot_info)
                slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
        if (parent->_sync)
                slave->mtd._sync = part_sync;
        if (!partno && !parent->dev.class && parent->_suspend &&
            parent->_resume) {
                slave->mtd._suspend = part_suspend;
                slave->mtd._resume = part_resume;
        }
        if (parent->_writev)
                slave->mtd._writev = part_writev;
        if (parent->_lock)
                slave->mtd._lock = part_lock;
        if (parent->_unlock)
                slave->mtd._unlock = part_unlock;
        if (parent->_is_locked)
                slave->mtd._is_locked = part_is_locked;
        if (parent->_block_isreserved)
                slave->mtd._block_isreserved = part_block_isreserved;
        if (parent->_block_isbad)
                slave->mtd._block_isbad = part_block_isbad;
        if (parent->_block_markbad)
                slave->mtd._block_markbad = part_block_markbad;
        if (parent->_max_bad_blocks)
                slave->mtd._max_bad_blocks = part_max_bad_blocks;

        if (parent->_get_device)
                slave->mtd._get_device = part_get_device;
        if (parent->_put_device)
                slave->mtd._put_device = part_put_device;

        slave->mtd._erase = part_erase;
        slave->parent = parent;
        slave->offset = part->offset;

        if (slave->offset == MTDPART_OFS_APPEND)
                slave->offset = cur_offset;
        if (slave->offset == MTDPART_OFS_NXTBLK) {
                tmp = cur_offset;
                slave->offset = cur_offset;
                remainder = do_div(tmp, wr_alignment);
                if (remainder) {
                        slave->offset += wr_alignment - remainder;
                        printk(KERN_NOTICE "Moving partition %d: "
                               "0x%012llx -> 0x%012llx\n", partno,
                               (unsigned long long)cur_offset, (unsigned long long)slave->offset);
                }
        }
        if (slave->offset == MTDPART_OFS_RETAIN) {
                slave->offset = cur_offset;
                if (parent->size - slave->offset >= slave->mtd.size) {
                        slave->mtd.size = parent->size - slave->offset
                                                        - slave->mtd.size;
                } else {
                        printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
                                part->name, parent->size - slave->offset,
                                slave->mtd.size);
                        /* register to preserve ordering */
                        goto out_register;
                }
        }
        if (slave->mtd.size == MTDPART_SIZ_FULL)
                slave->mtd.size = parent->size - slave->offset;

        printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n", (unsigned long long)slave->offset,
                (unsigned long long)(slave->offset + slave->mtd.size), slave->mtd.name);

        /* let's do some sanity checks */
        if (slave->offset >= parent->size) {
                /* let's register it anyway to preserve ordering */
                slave->offset = 0;
                slave->mtd.size = 0;

                /* Initialize ->erasesize to make add_mtd_device() happy. */
                slave->mtd.erasesize = parent->erasesize;

                printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
                        part->name);
                goto out_register;
        }
        if (slave->offset + slave->mtd.size > parent->size) {
                slave->mtd.size = parent->size - slave->offset;
                printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
                        part->name, parent->name, (unsigned long long)slave->mtd.size);
        }
        if (parent->numeraseregions > 1) {
                /* Deal with variable erase size stuff */
                int i, max = parent->numeraseregions;
                u64 end = slave->offset + slave->mtd.size;
                struct mtd_erase_region_info *regions = parent->eraseregions;

                /* Find the first erase regions which is part of this
                 * partition. */
                for (i = 0; i < max && regions[i].offset <= slave->offset; i++)
                        ;
                /* The loop searched for the region _behind_ the first one */
                if (i > 0)
                        i--;

                /* Pick biggest erasesize */
                for (; i < max && regions[i].offset < end; i++) {
                        if (slave->mtd.erasesize < regions[i].erasesize) {
                                slave->mtd.erasesize = regions[i].erasesize;
                        }
                }
                BUG_ON(slave->mtd.erasesize == 0);
        } else {
                /* Single erase size */
                slave->mtd.erasesize = parent->erasesize;
        }

        /*
         * Slave erasesize might differ from the master one if the master
         * exposes several regions with different erasesize. Adjust
         * wr_alignment accordingly.
         */
        if (!(slave->mtd.flags & MTD_NO_ERASE))
                wr_alignment = slave->mtd.erasesize;

        tmp = slave->offset;
        remainder = do_div(tmp, wr_alignment);
        if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
                /* Doesn't start on a boundary of major erase size */
                /* FIXME: Let it be writable if it is on a boundary of
                 * _minor_ erase size though */
                slave->mtd.flags &= ~MTD_WRITEABLE;
                printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
                        part->name);
        }

        tmp = slave->mtd.size;
        remainder = do_div(tmp, wr_alignment);
        if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
                slave->mtd.flags &= ~MTD_WRITEABLE;
                printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
                        part->name);
        }

        mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
        slave->mtd.ecc_step_size = parent->ecc_step_size;
        slave->mtd.ecc_strength = parent->ecc_strength;
        slave->mtd.bitflip_threshold = parent->bitflip_threshold;

        if (parent->_block_isbad) {
                uint64_t offs = 0;

                while (offs < slave->mtd.size) {
                        if (mtd_block_isreserved(parent, offs + slave->offset))
                                slave->mtd.ecc_stats.bbtblocks++;
                        else if (mtd_block_isbad(parent, offs + slave->offset))
                                slave->mtd.ecc_stats.badblocks++;
                        offs += slave->mtd.erasesize;
                }
        }

out_register:
        return slave;
}

static ssize_t mtd_partition_offset_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct mtd_info *mtd = dev_get_drvdata(dev);
        struct mtd_part *part = mtd_to_part(mtd);
        return snprintf(buf, PAGE_SIZE, "%lld\n", part->offset);
}

static DEVICE_ATTR(offset, S_IRUGO, mtd_partition_offset_show, NULL);

static const struct attribute *mtd_partition_attrs[] = {
        &dev_attr_offset.attr,
        NULL
};

static int mtd_add_partition_attrs(struct mtd_part *new)
{
        int ret = sysfs_create_files(&new->mtd.dev.kobj, mtd_partition_attrs);
        if (ret)
                printk(KERN_WARNING
                       "mtd: failed to create partition attrs, err=%d\n", ret);
        return ret;
}

int mtd_add_partition(struct mtd_info *parent, const char *name,
                      long long offset, long long length)
{
        struct mtd_partition part;
        struct mtd_part *new;
        int ret = 0;

        /* the direct offset is expected */
        if (offset == MTDPART_OFS_APPEND ||
            offset == MTDPART_OFS_NXTBLK)
                return -EINVAL;

        if (length == MTDPART_SIZ_FULL)
                length = parent->size - offset;

        if (length <= 0)
                return -EINVAL;

        memset(&part, 0, sizeof(part));
        part.name = name;
        part.size = length;
        part.offset = offset;

        new = allocate_partition(parent, &part, -1, offset);
        if (IS_ERR(new))
                return PTR_ERR(new);

        mutex_lock(&mtd_partitions_mutex);
        list_add(&new->list, &mtd_partitions);
        mutex_unlock(&mtd_partitions_mutex);

        ret = add_mtd_device(&new->mtd);
        if (ret)
                goto err_remove_part;

        mtd_add_partition_attrs(new);

        return 0;

err_remove_part:
        mutex_lock(&mtd_partitions_mutex);
        list_del(&new->list);
        mutex_unlock(&mtd_partitions_mutex);

        free_partition(new);

        return ret;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);

/**
 * __mtd_del_partition - delete MTD partition
 *
 * @priv: internal MTD struct for partition to be deleted
 *
 * This function must be called with the partitions mutex locked.
 */
static int __mtd_del_partition(struct mtd_part *priv)
{
        struct mtd_part *child, *next;
        int err;

        list_for_each_entry_safe(child, next, &mtd_partitions, list) {
                if (child->parent == &priv->mtd) {
                        err = __mtd_del_partition(child);
                        if (err)
                                return err;
                }
        }

        sysfs_remove_files(&priv->mtd.dev.kobj, mtd_partition_attrs);

        err = del_mtd_device(&priv->mtd);
        if (err)
                return err;

        list_del(&priv->list);
        free_partition(priv);

        return 0;
}

/*
 * This function unregisters and destroy all slave MTD objects which are
 * attached to the given MTD object.
 */
int del_mtd_partitions(struct mtd_info *mtd)
{
        struct mtd_part *slave, *next;
        int ret, err = 0;

        mutex_lock(&mtd_partitions_mutex);
        list_for_each_entry_safe(slave, next, &mtd_partitions, list)
                if (slave->parent == mtd) {
                        ret = __mtd_del_partition(slave);
                        if (ret < 0)
                                err = ret;
                }
        mutex_unlock(&mtd_partitions_mutex);

        return err;
}

int mtd_del_partition(struct mtd_info *mtd, int partno)
{
        struct mtd_part *slave, *next;
        int ret = -EINVAL;

        mutex_lock(&mtd_partitions_mutex);
        list_for_each_entry_safe(slave, next, &mtd_partitions, list)
                if ((slave->parent == mtd) &&
                    (slave->mtd.index == partno)) {
                        ret = __mtd_del_partition(slave);
                        break;
                }
        mutex_unlock(&mtd_partitions_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(mtd_del_partition);

/*
 * This function, given a master MTD object and a partition table, creates
 * and registers slave MTD objects which are bound to the master according to
 * the partition definitions.
 *
 * For historical reasons, this function's caller only registers the master
 * if the MTD_PARTITIONED_MASTER config option is set.
 */

int add_mtd_partitions(struct mtd_info *master,
                       const struct mtd_partition *parts,
                       int nbparts)
{
        struct mtd_part *slave;
        uint64_t cur_offset = 0;
        int i, ret;

        printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n", nbparts, master->name);

        for (i = 0; i < nbparts; i++) {
                slave = allocate_partition(master, parts + i, i, cur_offset);
                if (IS_ERR(slave)) {
                        ret = PTR_ERR(slave);
                        goto err_del_partitions;
                }

                mutex_lock(&mtd_partitions_mutex);
                list_add(&slave->list, &mtd_partitions);
                mutex_unlock(&mtd_partitions_mutex);

                ret = add_mtd_device(&slave->mtd);
                if (ret) {
                        mutex_lock(&mtd_partitions_mutex);
                        list_del(&slave->list);
                        mutex_unlock(&mtd_partitions_mutex);

                        free_partition(slave);
                        goto err_del_partitions;
                }

                mtd_add_partition_attrs(slave);
                /* Look for subpartitions */
                parse_mtd_partitions(&slave->mtd, parts[i].types, NULL);

                cur_offset = slave->offset + slave->mtd.size;
        }

        return 0;

err_del_partitions:
        del_mtd_partitions(master);

        return ret;
}

static DEFINE_SPINLOCK(part_parser_lock);
static LIST_HEAD(part_parsers);

static struct mtd_part_parser *mtd_part_parser_get(const char *name)
{
        struct mtd_part_parser *p, *ret = NULL;

        spin_lock(&part_parser_lock);

        list_for_each_entry(p, &part_parsers, list)
                if (!strcmp(p->name, name) && try_module_get(p->owner)) {
                        ret = p;
                        break;
                }

        spin_unlock(&part_parser_lock);

        return ret;
}

static inline void mtd_part_parser_put(const struct mtd_part_parser *p)
{
        module_put(p->owner);
}

/*
 * Many partition parsers just expected the core to kfree() all their data in
 * one chunk. Do that by default.
 */
static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts,
                                            int nr_parts)
{
        kfree(pparts);
}

int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner)
{
        p->owner = owner;

        if (!p->cleanup)
                p->cleanup = &mtd_part_parser_cleanup_default;

        spin_lock(&part_parser_lock);
        list_add(&p->list, &part_parsers);
        spin_unlock(&part_parser_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(__register_mtd_parser);

void deregister_mtd_parser(struct mtd_part_parser *p)
{
        spin_lock(&part_parser_lock);
        list_del(&p->list);
        spin_unlock(&part_parser_lock);
}
EXPORT_SYMBOL_GPL(deregister_mtd_parser);

/*
 * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
 * are changing this array!
 */
static const char * const default_mtd_part_types[] = {
        "cmdlinepart",
        "ofpart",
        NULL
};

/* Check DT only when looking for subpartitions. */
static const char * const default_subpartition_types[] = {
        "ofpart",
        NULL
};

static int mtd_part_do_parse(struct mtd_part_parser *parser,
                             struct mtd_info *master,
                             struct mtd_partitions *pparts,
                             struct mtd_part_parser_data *data)
{
        int ret;

        ret = (*parser->parse_fn)(master, &pparts->parts, data);
        pr_debug("%s: parser %s: %i\n", master->name, parser->name, ret);
        if (ret <= 0)
                return ret;

        pr_notice("%d %s partitions found on MTD device %s\n", ret,
                  parser->name, master->name);

        pparts->nr_parts = ret;
        pparts->parser = parser;

        return ret;
}

/**
 * mtd_part_get_compatible_parser - find MTD parser by a compatible string
 *
 * @compat: compatible string describing partitions in a device tree
 *
 * MTD parsers can specify supported partitions by providing a table of
 * compatibility strings. This function finds a parser that advertises support
 * for a passed value of "compatible".
 */
static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
{
        struct mtd_part_parser *p, *ret = NULL;

        spin_lock(&part_parser_lock);

        list_for_each_entry(p, &part_parsers, list) {
                const struct of_device_id *matches;

                matches = p->of_match_table;
                if (!matches)
                        continue;

                for (; matches->compatible[0]; matches++) {
                        if (!strcmp(matches->compatible, compat) &&
                            try_module_get(p->owner)) {
                                ret = p;
                                break;
                        }
                }

                if (ret)
                        break;
        }

        spin_unlock(&part_parser_lock);

        return ret;
}

static int mtd_part_of_parse(struct mtd_info *master,
                             struct mtd_partitions *pparts)
{
        struct mtd_part_parser *parser;
        struct device_node *np;
        struct property *prop;
        const char *compat;
        const char *fixed = "fixed-partitions";
        int ret, err = 0;

        np = mtd_get_of_node(master);
        if (mtd_is_partition(master))
                of_node_get(np);
        else
                np = of_get_child_by_name(np, "partitions");

        of_property_for_each_string(np, "compatible", prop, compat) {
                parser = mtd_part_get_compatible_parser(compat);
                if (!parser)
                        continue;
                ret = mtd_part_do_parse(parser, master, pparts, NULL);
                if (ret > 0) {
                        of_node_put(np);
                        return ret;
                }
                mtd_part_parser_put(parser);
                if (ret < 0 && !err)
                        err = ret;
        }
        of_node_put(np);

        /*
         * For backward compatibility we have to try the "fixed-partitions"
         * parser. It supports old DT format with partitions specified as a
         * direct subnodes of a flash device DT node without any compatibility
         * specified we could match.
         */
        parser = mtd_part_parser_get(fixed);
        if (!parser && !request_module("%s", fixed))
                parser = mtd_part_parser_get(fixed);
        if (parser) {
                ret = mtd_part_do_parse(parser, master, pparts, NULL);
                if (ret > 0)
                        return ret;
                mtd_part_parser_put(parser);
                if (ret < 0 && !err)
                        err = ret;
        }

        return err;
}

/**
 * parse_mtd_partitions - parse and register MTD partitions
 *
 * @master: the master partition (describes whole MTD device)
 * @types: names of partition parsers to try or %NULL
 * @data: MTD partition parser-specific data
 *
 * This function tries to find & register partitions on MTD device @master. It
 * uses MTD partition parsers, specified in @types. However, if @types is %NULL,
 * then the default list of parsers is used. The default list contains only the
 * "cmdlinepart" and "ofpart" parsers ATM.
 * Note: If there are more then one parser in @types, the kernel only takes the
 * partitions parsed out by the first parser.
 *
 * This function may return:
 * o a negative error code in case of failure
 * o number of found partitions otherwise
 */
int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
                         struct mtd_part_parser_data *data)
{
        struct mtd_partitions pparts = { };
        struct mtd_part_parser *parser;
        int ret, err = 0;

        if (!types)
                types = mtd_is_partition(master) ? default_subpartition_types :
                        default_mtd_part_types;

        for ( ; *types; types++) {
                /*
                 * ofpart is a special type that means OF partitioning info
                 * should be used. It requires a bit different logic so it is
                 * handled in a separated function.
                 */
                if (!strcmp(*types, "ofpart")) {
                        ret = mtd_part_of_parse(master, &pparts);
                } else {
                        pr_debug("%s: parsing partitions %s\n", master->name,
                                 *types);
                        parser = mtd_part_parser_get(*types);
                        if (!parser && !request_module("%s", *types))
                                parser = mtd_part_parser_get(*types);
                        pr_debug("%s: got parser %s\n", master->name,
                                parser ? parser->name : NULL);
                        if (!parser)
                                continue;
                        ret = mtd_part_do_parse(parser, master, &pparts, data);
                        if (ret <= 0)
                                mtd_part_parser_put(parser);
                }
                /* Found partitions! */
                if (ret > 0) {
                        err = add_mtd_partitions(master, pparts.parts,
                                                 pparts.nr_parts);
                        mtd_part_parser_cleanup(&pparts);
                        return err ? err : pparts.nr_parts;
                }
                /*
                 * Stash the first error we see; only report it if no parser
                 * succeeds
                 */
                if (ret < 0 && !err)
                        err = ret;
        }
        return err;
}

void mtd_part_parser_cleanup(struct mtd_partitions *parts)
{
        const struct mtd_part_parser *parser;

        if (!parts)
                return;

        parser = parts->parser;
        if (parser) {
                if (parser->cleanup)
                        parser->cleanup(parts->parts, parts->nr_parts);

                mtd_part_parser_put(parser);
        }
}

int mtd_is_partition(const struct mtd_info *mtd)
{
        struct mtd_part *part;
        int ispart = 0;

        mutex_lock(&mtd_partitions_mutex);
        list_for_each_entry(part, &mtd_partitions, list)
                if (&part->mtd == mtd) {
                        ispart = 1;
                        break;
                }
        mutex_unlock(&mtd_partitions_mutex);

        return ispart;
}
EXPORT_SYMBOL_GPL(mtd_is_partition);

/* Returns the size of the entire flash chip */
uint64_t mtd_get_device_size(const struct mtd_info *mtd)
{
        if (!mtd_is_partition(mtd))
                return mtd->size;

        return mtd_get_device_size(mtd_to_part(mtd)->parent);
}
EXPORT_SYMBOL_GPL(mtd_get_device_size);