// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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.
 */

#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>

#include "ofpart_bcm4908.h"
#include "ofpart_linksys_ns.h"

struct fixed_partitions_quirks {
        int (*post_parse)(struct mtd_info *mtd, struct mtd_partition *parts, int nr_parts);
};

#ifdef CONFIG_MTD_OF_PARTS_BCM4908
static struct fixed_partitions_quirks bcm4908_partitions_quirks = {
        .post_parse = bcm4908_partitions_post_parse,
};
#endif

#ifdef CONFIG_MTD_OF_PARTS_LINKSYS_NS
static struct fixed_partitions_quirks linksys_ns_partitions_quirks = {
        .post_parse = linksys_ns_partitions_post_parse,
};
#endif

static const struct of_device_id parse_ofpart_match_table[];

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

static int parse_fixed_partitions(struct mtd_info *master,
                                  const struct mtd_partition **pparts,
                                  struct mtd_part_parser_data *data)
{
        const struct fixed_partitions_quirks *quirks;
        const struct of_device_id *of_id;
        struct mtd_partition *parts;
        struct device_node *mtd_node;
        struct device_node *ofpart_node;
        const char *partname;
        struct device_node *pp;
        int nr_parts, i, ret = 0;
        bool dedicated = true;

        /* Pull of_node from the master device node */
        mtd_node = mtd_get_of_node(master);
        if (!mtd_node)
                return 0;

        if (!master->parent) { /* Master */
                ofpart_node = of_get_child_by_name(mtd_node, "partitions");
                if (!ofpart_node) {
                        /*
                         * We might get here even when ofpart isn't used at all (e.g.,
                         * when using another parser), so don't be louder than
                         * KERN_DEBUG
                         */
                        pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
                                master->name, mtd_node);
                        ofpart_node = mtd_node;
                        dedicated = false;
                }
        } else { /* Partition */
                ofpart_node = mtd_node;
        }

        of_id = of_match_node(parse_ofpart_match_table, ofpart_node);
        if (dedicated && !of_id) {
                /* The 'partitions' subnode might be used by another parser */
                of_node_put(ofpart_node);
                return 0;
        }

        quirks = of_id ? of_id->data : NULL;

        /* First count the subnodes */
        nr_parts = 0;
        for_each_child_of_node(ofpart_node,  pp) {
                if (!dedicated && node_has_compatible(pp))
                        continue;

                nr_parts++;
        }

        if (nr_parts == 0) {
                if (dedicated)
                        of_node_put(ofpart_node);
                return 0;
        }

        parts = kzalloc_objs(*parts, nr_parts);
        if (!parts) {
                if (dedicated)
                        of_node_put(ofpart_node);
                return -ENOMEM;
        }

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

                if (!dedicated && node_has_compatible(pp))
                        continue;

                reg = of_get_property(pp, "reg", &len);
                if (!reg) {
                        if (dedicated) {
                                pr_debug("%s: ofpart partition %pOF (%pOF) missing reg property.\n",
                                         master->name, pp,
                                         mtd_node);
                                goto ofpart_fail;
                        } else {
                                nr_parts--;
                                continue;
                        }
                }

                a_cells = of_n_addr_cells(pp);
                s_cells = of_n_size_cells(pp);
                if (!dedicated && s_cells == 0) {
                        /*
                         * This is a ugly workaround to not create
                         * regression on devices that are still creating
                         * partitions as direct children of the nand controller.
                         * This can happen in case the nand controller node has
                         * #size-cells equal to 0 and the firmware (e.g.
                         * U-Boot) just add the partitions there assuming
                         * 32-bit addressing.
                         *
                         * If you get this warning your firmware and/or DTS
                         * should be really fixed.
                         *
                         * This is working only for devices smaller than 4GiB.
                         */
                        pr_warn("%s: ofpart partition %pOF (%pOF) #size-cells is wrongly set to <0>, assuming <1> for parsing partitions.\n",
                                master->name, pp, mtd_node);
                        s_cells = 1;
                }
                if (len / 4 != a_cells + s_cells) {
                        pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
                                 master->name, pp,
                                 mtd_node);
                        goto ofpart_fail;
                }

                parts[i].offset = of_read_number(reg, a_cells);
                parts[i].size = of_read_number(reg + a_cells, s_cells);
                parts[i].of_node = pp;

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

                if (of_property_read_bool(pp, "read-only"))
                        parts[i].mask_flags |= MTD_WRITEABLE;

                if (of_property_read_bool(pp, "lock"))
                        parts[i].mask_flags |= MTD_POWERUP_LOCK;

                if (of_property_read_bool(pp, "slc-mode"))
                        parts[i].add_flags |= MTD_SLC_ON_MLC_EMULATION;

                i++;
        }

        if (!nr_parts)
                goto ofpart_none;

        if (quirks && quirks->post_parse)
                quirks->post_parse(master, parts, nr_parts);

        if (dedicated)
                of_node_put(ofpart_node);

        *pparts = parts;
        return nr_parts;

ofpart_fail:
        pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
               master->name, pp, mtd_node);
        ret = -EINVAL;
ofpart_none:
        if (dedicated)
                of_node_put(ofpart_node);
        of_node_put(pp);
        kfree(parts);
        return ret;
}

static const struct of_device_id parse_ofpart_match_table[] = {
        /* Generic */
        { .compatible = "fixed-partitions" },
        /* Customized */
#ifdef CONFIG_MTD_OF_PARTS_BCM4908
        { .compatible = "brcm,bcm4908-partitions", .data = &bcm4908_partitions_quirks, },
#endif
#ifdef CONFIG_MTD_OF_PARTS_LINKSYS_NS
        { .compatible = "linksys,ns-partitions", .data = &linksys_ns_partitions_quirks, },
#endif
        {},
};
MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);

static struct mtd_part_parser ofpart_parser = {
        .parse_fn = parse_fixed_partitions,
        .name = "fixed-partitions",
        .of_match_table = parse_ofpart_match_table,
};

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

        /* Pull of_node from the master device node */
        dp = mtd_get_of_node(master);
        if (!dp)
                return 0;

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

        pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);

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

        parts = kzalloc_objs(*parts, nr_parts);
        if (!parts)
                return -ENOMEM;

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

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

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

                        parts[i].name = names;
                        plen -= len;
                        names += len;
                } else {
                        parts[i].name = "unnamed";
                }

                part++;
        }

        *pparts = parts;
        return nr_parts;
}

static struct mtd_part_parser ofoldpart_parser = {
        .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("fixed-partitions");
MODULE_ALIAS("ofoldpart");