/*
 * Flash partitions described by the OF (or flattened) device tree
 *
 * Copyright © 2006 MontaVista Software Inc.
 * Author: Vitaly Wool <vwool@ru.mvista.com>
 *
 * Revised to handle newer style flash binding by:
 *   Copyright © 2007 David Gibson, IBM Corporation.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/mtd/mtd.h>
#include <linux/slab.h>
#include <linux/mtd/partitions.h>

static bool node_has_compatible(struct device_node *pp)
{
        return of_get_property(pp, "compatible", NULL);
}

static int parse_ofpart_partitions(struct mtd_info *master,
                                   struct mtd_partition **pparts,
                                   struct mtd_part_parser_data *data)
{
        struct device_node *node;
        const char *partname;
        struct device_node *pp;
        int nr_parts, i;


        if (!data)
                return 0;

        node = data->of_node;
        if (!node)
                return 0;

        /* First count the subnodes */
        nr_parts = 0;
        for_each_child_of_node(node,  pp) {
                if (node_has_compatible(pp))
                        continue;

                nr_parts++;
        }

        if (nr_parts == 0)
                return 0;

        *pparts = kzalloc(nr_parts * sizeof(**pparts), GFP_KERNEL);
        if (!*pparts)
                return -ENOMEM;

        i = 0;
        for_each_child_of_node(node,  pp) {
                const __be32 *reg;
                int len;
                int a_cells, s_cells;

                if (node_has_compatible(pp))
                        continue;

                reg = of_get_property(pp, "reg", &len);
                if (!reg) {
                        nr_parts--;
                        continue;
                }

                a_cells = of_n_addr_cells(pp);
                s_cells = of_n_size_cells(pp);
                (*pparts)[i].offset = of_read_number(reg, a_cells);
                (*pparts)[i].size = of_read_number(reg + a_cells, s_cells);

                partname = of_get_property(pp, "label", &len);
                if (!partname)
                        partname = of_get_property(pp, "name", &len);
                (*pparts)[i].name = partname;

                if (of_get_property(pp, "read-only", &len))
                        (*pparts)[i].mask_flags |= MTD_WRITEABLE;

                if (of_get_property(pp, "lock", &len))
                        (*pparts)[i].mask_flags |= MTD_POWERUP_LOCK;

                i++;
        }

        if (!i) {
                of_node_put(pp);
                pr_err("No valid partition found on %s\n", node->full_name);
                kfree(*pparts);
                *pparts = NULL;
                return -EINVAL;
        }

        return nr_parts;
}

static struct mtd_part_parser ofpart_parser = {
        .owner = THIS_MODULE,
        .parse_fn = parse_ofpart_partitions,
        .name = "ofpart",
};

static int parse_ofoldpart_partitions(struct mtd_info *master,
                                      struct mtd_partition **pparts,
                                      struct mtd_part_parser_data *data)
{
        struct device_node *dp;
        int i, plen, nr_parts;
        const struct {
                __be32 offset, len;
        } *part;
        const char *names;

        if (!data)
                return 0;

        dp = data->of_node;
        if (!dp)
                return 0;

        part = of_get_property(dp, "partitions", &plen);
        if (!part)
                return 0; /* No partitions found */

        pr_warning("Device tree uses obsolete partition map binding: %s\n",
                        dp->full_name);

        nr_parts = plen / sizeof(part[0]);

        *pparts = kzalloc(nr_parts * sizeof(*(*pparts)), GFP_KERNEL);
        if (!*pparts)
                return -ENOMEM;

        names = of_get_property(dp, "partition-names", &plen);

        for (i = 0; i < nr_parts; i++) {
                (*pparts)[i].offset = be32_to_cpu(part->offset);
                (*pparts)[i].size   = be32_to_cpu(part->len) & ~1;
                /* bit 0 set signifies read only partition */
                if (be32_to_cpu(part->len) & 1)
                        (*pparts)[i].mask_flags = MTD_WRITEABLE;

                if (names && (plen > 0)) {
                        int len = strlen(names) + 1;

                        (*pparts)[i].name = names;
                        plen -= len;
                        names += len;
                } else {
                        (*pparts)[i].name = "unnamed";
                }

                part++;
        }

        return nr_parts;
}

static struct mtd_part_parser ofoldpart_parser = {
        .owner = THIS_MODULE,
        .parse_fn = parse_ofoldpart_partitions,
        .name = "ofoldpart",
};

static int __init ofpart_parser_init(void)
{
        register_mtd_parser(&ofpart_parser);
        register_mtd_parser(&ofoldpart_parser);
        return 0;
}

static void __exit ofpart_parser_exit(void)
{
        deregister_mtd_parser(&ofpart_parser);
        deregister_mtd_parser(&ofoldpart_parser);
}

module_init(ofpart_parser_init);
module_exit(ofpart_parser_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
MODULE_AUTHOR("Vitaly Wool, David Gibson");
/*
 * When MTD core cannot find the requested parser, it tries to load the module
 * with the same name. Since we provide the ofoldpart parser, we should have
 * the corresponding alias.
 */
MODULE_ALIAS("ofoldpart");