/*
 * 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>

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

/* Our partition node structure */
struct mtd_part {
        struct mtd_info mtd;
        struct mtd_info *master;
        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 with this macro.
 */
#define PART(x)  ((struct mtd_part *)(x))


/*
 * 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 = PART(mtd);
        struct mtd_ecc_stats stats;
        int res;

        stats = part->master->ecc_stats;

        if (from >= mtd->size)
                len = 0;
        else if (from + len > mtd->size)
                len = mtd->size - from;
        res = part->master->read(part->master, from + part->offset,
                                   len, retlen, buf);
        if (unlikely(res)) {
                if (res == -EUCLEAN)
                        mtd->ecc_stats.corrected += part->master->ecc_stats.corrected - stats.corrected;
                if (res == -EBADMSG)
                        mtd->ecc_stats.failed += part->master->ecc_stats.failed - stats.failed;
        }
        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 = PART(mtd);
        if (from >= mtd->size)
                len = 0;
        else if (from + len > mtd->size)
                len = mtd->size - from;
        return part->master->point (part->master, from + part->offset,
                                    len, retlen, virt, phys);
}

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

        part->master->unpoint(part->master, from + part->offset, len);
}

static unsigned long part_get_unmapped_area(struct mtd_info *mtd,
                                            unsigned long len,
                                            unsigned long offset,
                                            unsigned long flags)
{
        struct mtd_part *part = PART(mtd);

        offset += part->offset;
        return part->master->get_unmapped_area(part->master, len, offset,
                                               flags);
}

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

        if (from >= mtd->size)
                return -EINVAL;
        if (ops->datbuf && from + ops->len > mtd->size)
                return -EINVAL;

        /*
         * If OOB is also requested, make sure that we do not read past the end
         * of this partition.
         */
        if (ops->oobbuf) {
                size_t len, pages;

                if (ops->mode == MTD_OOB_AUTO)
                        len = mtd->oobavail;
                else
                        len = mtd->oobsize;
                pages = mtd_div_by_ws(mtd->size, mtd);
                pages -= mtd_div_by_ws(from, mtd);
                if (ops->ooboffs + ops->ooblen > pages * len)
                        return -EINVAL;
        }

        res = part->master->read_oob(part->master, from + part->offset, ops);
        if (unlikely(res)) {
                if (res == -EUCLEAN)
                        mtd->ecc_stats.corrected++;
                if (res == -EBADMSG)
                        mtd->ecc_stats.failed++;
        }
        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 = PART(mtd);
        return part->master->read_user_prot_reg(part->master, from,
                                        len, retlen, buf);
}

static int part_get_user_prot_info(struct mtd_info *mtd,
                struct otp_info *buf, size_t len)
{
        struct mtd_part *part = PART(mtd);
        return part->master->get_user_prot_info(part->master, buf, len);
}

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 = PART(mtd);
        return part->master->read_fact_prot_reg(part->master, from,
                                        len, retlen, buf);
}

static int part_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
                size_t len)
{
        struct mtd_part *part = PART(mtd);
        return part->master->get_fact_prot_info(part->master, buf, len);
}

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 = PART(mtd);
        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;
        if (to >= mtd->size)
                len = 0;
        else if (to + len > mtd->size)
                len = mtd->size - to;
        return part->master->write(part->master, 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 = PART(mtd);
        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;
        if (to >= mtd->size)
                len = 0;
        else if (to + len > mtd->size)
                len = mtd->size - to;
        return part->master->panic_write(part->master, 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 = PART(mtd);

        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;

        if (to >= mtd->size)
                return -EINVAL;
        if (ops->datbuf && to + ops->len > mtd->size)
                return -EINVAL;
        return part->master->write_oob(part->master, 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 = PART(mtd);
        return part->master->write_user_prot_reg(part->master, 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 = PART(mtd);
        return part->master->lock_user_prot_reg(part->master, 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 = PART(mtd);
        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;
        return part->master->writev(part->master, vecs, count,
                                        to + part->offset, retlen);
}

static int part_erase(struct mtd_info *mtd, struct erase_info *instr)
{
        struct mtd_part *part = PART(mtd);
        int ret;
        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;
        if (instr->addr >= mtd->size)
                return -EINVAL;
        instr->addr += part->offset;
        ret = part->master->erase(part->master, instr);
        if (ret) {
                if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
                        instr->fail_addr -= part->offset;
                instr->addr -= part->offset;
        }
        return ret;
}

void mtd_erase_callback(struct erase_info *instr)
{
        if (instr->mtd->erase == part_erase) {
                struct mtd_part *part = PART(instr->mtd);

                if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
                        instr->fail_addr -= part->offset;
                instr->addr -= part->offset;
        }
        if (instr->callback)
                instr->callback(instr);
}
EXPORT_SYMBOL_GPL(mtd_erase_callback);

static int part_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = PART(mtd);
        if ((len + ofs) > mtd->size)
                return -EINVAL;
        return part->master->lock(part->master, ofs + part->offset, len);
}

static int part_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = PART(mtd);
        if ((len + ofs) > mtd->size)
                return -EINVAL;
        return part->master->unlock(part->master, ofs + part->offset, len);
}

static int part_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        struct mtd_part *part = PART(mtd);
        if ((len + ofs) > mtd->size)
                return -EINVAL;
        return part->master->is_locked(part->master, ofs + part->offset, len);
}

static void part_sync(struct mtd_info *mtd)
{
        struct mtd_part *part = PART(mtd);
        part->master->sync(part->master);
}

static int part_suspend(struct mtd_info *mtd)
{
        struct mtd_part *part = PART(mtd);
        return part->master->suspend(part->master);
}

static void part_resume(struct mtd_info *mtd)
{
        struct mtd_part *part = PART(mtd);
        part->master->resume(part->master);
}

static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
        struct mtd_part *part = PART(mtd);
        if (ofs >= mtd->size)
                return -EINVAL;
        ofs += part->offset;
        return part->master->block_isbad(part->master, ofs);
}

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

        if (!(mtd->flags & MTD_WRITEABLE))
                return -EROFS;
        if (ofs >= mtd->size)
                return -EINVAL;
        ofs += part->offset;
        res = part->master->block_markbad(part->master, ofs);
        if (!res)
                mtd->ecc_stats.badblocks++;
        return res;
}

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

/*
 * This function unregisters and destroy all slave MTD objects which are
 * attached to the given master MTD object.
 */

int del_mtd_partitions(struct mtd_info *master)
{
        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->master == master) {
                        ret = del_mtd_device(&slave->mtd);
                        if (ret < 0) {
                                err = ret;
                                continue;
                        }
                        list_del(&slave->list);
                        free_partition(slave);
                }
        mutex_unlock(&mtd_partitions_mutex);

        return err;
}
EXPORT_SYMBOL(del_mtd_partitions);

static struct mtd_part *allocate_partition(struct mtd_info *master,
                        const struct mtd_partition *part, int partno,
                        uint64_t cur_offset)
{
        struct mtd_part *slave;
        char *name;

        /* 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",
                       master->name);
                kfree(name);
                kfree(slave);
                return ERR_PTR(-ENOMEM);
        }

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

        slave->mtd.name = name;
        slave->mtd.owner = master->owner;
        slave->mtd.backing_dev_info = master->backing_dev_info;

        /* NOTE:  we don't arrange MTDs as a tree; it'd be error-prone
         * to have the same data be in two different partitions.
         */
        slave->mtd.dev.parent = master->dev.parent;

        slave->mtd.read = part_read;
        slave->mtd.write = part_write;

        if (master->panic_write)
                slave->mtd.panic_write = part_panic_write;

        if (master->point && master->unpoint) {
                slave->mtd.point = part_point;
                slave->mtd.unpoint = part_unpoint;
        }

        if (master->get_unmapped_area)
                slave->mtd.get_unmapped_area = part_get_unmapped_area;
        if (master->read_oob)
                slave->mtd.read_oob = part_read_oob;
        if (master->write_oob)
                slave->mtd.write_oob = part_write_oob;
        if (master->read_user_prot_reg)
                slave->mtd.read_user_prot_reg = part_read_user_prot_reg;
        if (master->read_fact_prot_reg)
                slave->mtd.read_fact_prot_reg = part_read_fact_prot_reg;
        if (master->write_user_prot_reg)
                slave->mtd.write_user_prot_reg = part_write_user_prot_reg;
        if (master->lock_user_prot_reg)
                slave->mtd.lock_user_prot_reg = part_lock_user_prot_reg;
        if (master->get_user_prot_info)
                slave->mtd.get_user_prot_info = part_get_user_prot_info;
        if (master->get_fact_prot_info)
                slave->mtd.get_fact_prot_info = part_get_fact_prot_info;
        if (master->sync)
                slave->mtd.sync = part_sync;
        if (!partno && !master->dev.class && master->suspend && master->resume) {
                        slave->mtd.suspend = part_suspend;
                        slave->mtd.resume = part_resume;
        }
        if (master->writev)
                slave->mtd.writev = part_writev;
        if (master->lock)
                slave->mtd.lock = part_lock;
        if (master->unlock)
                slave->mtd.unlock = part_unlock;
        if (master->is_locked)
                slave->mtd.is_locked = part_is_locked;
        if (master->block_isbad)
                slave->mtd.block_isbad = part_block_isbad;
        if (master->block_markbad)
                slave->mtd.block_markbad = part_block_markbad;
        slave->mtd.erase = part_erase;
        slave->master = master;
        slave->offset = part->offset;

        if (slave->offset == MTDPART_OFS_APPEND)
                slave->offset = cur_offset;
        if (slave->offset == MTDPART_OFS_NXTBLK) {
                slave->offset = cur_offset;
                if (mtd_mod_by_eb(cur_offset, master) != 0) {
                        /* Round up to next erasesize */
                        slave->offset = (mtd_div_by_eb(cur_offset, master) + 1) * master->erasesize;
                        printk(KERN_NOTICE "Moving partition %d: "
                               "0x%012llx -> 0x%012llx\n", partno,
                               (unsigned long long)cur_offset, (unsigned long long)slave->offset);
                }
        }
        if (slave->mtd.size == MTDPART_SIZ_FULL)
                slave->mtd.size = master->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 >= master->size) {
                /* let's register it anyway to preserve ordering */
                slave->offset = 0;
                slave->mtd.size = 0;
                printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
                        part->name);
                goto out_register;
        }
        if (slave->offset + slave->mtd.size > master->size) {
                slave->mtd.size = master->size - slave->offset;
                printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
                        part->name, master->name, (unsigned long long)slave->mtd.size);
        }
        if (master->numeraseregions > 1) {
                /* Deal with variable erase size stuff */
                int i, max = master->numeraseregions;
                u64 end = slave->offset + slave->mtd.size;
                struct mtd_erase_region_info *regions = master->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 = master->erasesize;
        }

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

        slave->mtd.ecclayout = master->ecclayout;
        if (master->block_isbad) {
                uint64_t offs = 0;

                while (offs < slave->mtd.size) {
                        if (master->block_isbad(master,
                                                offs + slave->offset))
                                slave->mtd.ecc_stats.badblocks++;
                        offs += slave->mtd.erasesize;
                }
        }

out_register:
        return slave;
}

int mtd_add_partition(struct mtd_info *master, char *name,
                      long long offset, long long length)
{
        struct mtd_partition part;
        struct mtd_part *p, *new;
        uint64_t start, end;
        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 = master->size - offset;

        if (length <= 0)
                return -EINVAL;

        part.name = name;
        part.size = length;
        part.offset = offset;
        part.mask_flags = 0;
        part.ecclayout = NULL;

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

        start = offset;
        end = offset + length;

        mutex_lock(&mtd_partitions_mutex);
        list_for_each_entry(p, &mtd_partitions, list)
                if (p->master == master) {
                        if ((start >= p->offset) &&
                            (start < (p->offset + p->mtd.size)))
                                goto err_inv;

                        if ((end >= p->offset) &&
                            (end < (p->offset + p->mtd.size)))
                                goto err_inv;
                }

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

        add_mtd_device(&new->mtd);

        return ret;
err_inv:
        mutex_unlock(&mtd_partitions_mutex);
        free_partition(new);
        return -EINVAL;
}
EXPORT_SYMBOL_GPL(mtd_add_partition);

int mtd_del_partition(struct mtd_info *master, 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->master == master) &&
                    (slave->mtd.index == partno)) {
                        ret = del_mtd_device(&slave->mtd);
                        if (ret < 0)
                                break;

                        list_del(&slave->list);
                        free_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.
 *
 * We don't register the master, or expect the caller to have done so,
 * for reasons of data integrity.
 */

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;

        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))
                        return PTR_ERR(slave);

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

                add_mtd_device(&slave->mtd);

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

        return 0;
}
EXPORT_SYMBOL(add_mtd_partitions);

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

static struct mtd_part_parser *get_partition_parser(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;
}

int register_mtd_parser(struct mtd_part_parser *p)
{
        spin_lock(&part_parser_lock);
        list_add(&p->list, &part_parsers);
        spin_unlock(&part_parser_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(register_mtd_parser);

int deregister_mtd_parser(struct mtd_part_parser *p)
{
        spin_lock(&part_parser_lock);
        list_del(&p->list);
        spin_unlock(&part_parser_lock);
        return 0;
}
EXPORT_SYMBOL_GPL(deregister_mtd_parser);

int parse_mtd_partitions(struct mtd_info *master, const char **types,
                         struct mtd_partition **pparts, unsigned long origin)
{
        struct mtd_part_parser *parser;
        int ret = 0;

        for ( ; ret <= 0 && *types; types++) {
                parser = get_partition_parser(*types);
                if (!parser && !request_module("%s", *types))
                                parser = get_partition_parser(*types);
                if (!parser) {
                        printk(KERN_NOTICE "%s partition parsing not available\n",
                               *types);
                        continue;
                }
                ret = (*parser->parse_fn)(master, pparts, origin);
                if (ret > 0) {
                        printk(KERN_NOTICE "%d %s partitions found on MTD device %s\n",
                               ret, parser->name, master->name);
                }
                put_partition_parser(parser);
        }
        return ret;
}
EXPORT_SYMBOL_GPL(parse_mtd_partitions);

int mtd_is_partition(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);