// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2014
 * Heiko Schocher, DENX Software Engineering, hs@denx.de.
 */
#include <common.h>
#include <env.h>
#include <log.h>
#include <malloc.h>
#include <dm/device.h>
#include <dm/uclass-internal.h>
#include <linux/err.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <mtd.h>

#define MTD_NAME_MAX_LEN 20

void board_mtdparts_default(const char **mtdids, const char **mtdparts);

static const char *get_mtdids(void)
{
        __maybe_unused const char *mtdparts = NULL;
        const char *mtdids = env_get("mtdids");

        if (mtdids)
                return mtdids;

#if defined(CONFIG_SYS_MTDPARTS_RUNTIME)
        board_mtdparts_default(&mtdids, &mtdparts);
#elif defined(MTDIDS_DEFAULT)
        mtdids = MTDIDS_DEFAULT;
#elif defined(CONFIG_MTDIDS_DEFAULT)
        mtdids = CONFIG_MTDIDS_DEFAULT;
#endif

        if (mtdids)
                env_set("mtdids", mtdids);

        return mtdids;
}

/**
 * mtd_search_alternate_name - Search an alternate name for @mtdname thanks to
 *                             the mtdids legacy environment variable.
 *
 * The mtdids string is a list of comma-separated 'dev_id=mtd_id' tupples.
 * Check if one of the mtd_id matches mtdname, in this case save dev_id in
 * altname.
 *
 * @mtdname: Current MTD device name
 * @altname: Alternate name to return
 * @max_len: Length of the alternate name buffer
 *
 * @return 0 on success, an error otherwise.
 */
int mtd_search_alternate_name(const char *mtdname, char *altname,
                              unsigned int max_len)
{
        const char *mtdids, *equal, *comma, *dev_id, *mtd_id;
        int dev_id_len, mtd_id_len;

        mtdids = get_mtdids();
        if (!mtdids)
                return -EINVAL;

        do {
                /* Find the '=' sign */
                dev_id = mtdids;
                equal = strchr(dev_id, '=');
                if (!equal)
                        break;
                dev_id_len = equal - mtdids;
                mtd_id = equal + 1;

                /* Find the end of the tupple */
                comma = strchr(mtdids, ',');
                if (comma)
                        mtd_id_len = comma - mtd_id;
                else
                        mtd_id_len = &mtdids[strlen(mtdids)] - mtd_id + 1;

                if (!dev_id_len || !mtd_id_len)
                        return -EINVAL;

                if (dev_id_len + 1 > max_len)
                        continue;

                /* Compare the name we search with the current mtd_id */
                if (!strncmp(mtdname, mtd_id, mtd_id_len)) {
                        strncpy(altname, dev_id, dev_id_len);
                        altname[dev_id_len] = 0;

                        return 0;
                }

                /* Go to the next tupple */
                mtdids = comma + 1;
        } while (comma);

        return -EINVAL;
}

#if IS_ENABLED(CONFIG_DM_MTD)
static void mtd_probe_uclass_mtd_devs(void)
{
        struct udevice *dev;
        int idx = 0;

        /* Probe devices with DM compliant drivers */
        while (!uclass_find_device(UCLASS_MTD, idx, &dev) && dev) {
                mtd_probe(dev);
                idx++;
        }
}
#else
static void mtd_probe_uclass_mtd_devs(void) { }
#endif

#if defined(CONFIG_MTD_PARTITIONS)

#define MTDPARTS_MAXLEN         512

static const char *get_mtdparts(void)
{
        __maybe_unused const char *mtdids = NULL;
        static char tmp_parts[MTDPARTS_MAXLEN];
        const char *mtdparts = NULL;

        if (gd->flags & GD_FLG_ENV_READY)
                mtdparts = env_get("mtdparts");
        else if (env_get_f("mtdparts", tmp_parts, sizeof(tmp_parts)) != -1)
                mtdparts = tmp_parts;

        if (mtdparts)
                return mtdparts;

#if defined(CONFIG_SYS_MTDPARTS_RUNTIME)
        board_mtdparts_default(&mtdids, &mtdparts);
#elif defined(MTDPARTS_DEFAULT)
        mtdparts = MTDPARTS_DEFAULT;
#elif defined(CONFIG_MTDPARTS_DEFAULT)
        mtdparts = CONFIG_MTDPARTS_DEFAULT;
#endif

        if (mtdparts)
                env_set("mtdparts", mtdparts);

        return mtdparts;
}

static int mtd_del_parts(struct mtd_info *mtd, bool quiet)
{
        int ret;

        if (!mtd_has_partitions(mtd))
                return 0;

        /* do not delete partitions if they are in use. */
        if (mtd_partitions_used(mtd)) {
                if (!quiet)
                        printf("\"%s\" partitions still in use, can't delete them\n",
                               mtd->name);
                return -EACCES;
        }

        ret = del_mtd_partitions(mtd);
        if (ret)
                return ret;

        return 1;
}

static bool mtd_del_all_parts_failed;

static void mtd_del_all_parts(void)
{
        struct mtd_info *mtd;
        int ret = 0;

        mtd_del_all_parts_failed = false;

        /*
         * It is not safe to remove entries from the mtd_for_each_device loop
         * as it uses idr indexes and the partitions removal is done in bulk
         * (all partitions of one device at the same time), so break and
         * iterate from start each time a new partition is found and deleted.
         */
        do {
                mtd_for_each_device(mtd) {
                        ret = mtd_del_parts(mtd, false);
                        if (ret > 0)
                                break;
                        else if (ret < 0)
                                mtd_del_all_parts_failed = true;
                }
        } while (ret > 0);
}

int mtd_probe_devices(void)
{
        static char *old_mtdparts;
        static char *old_mtdids;
        const char *mtdparts = get_mtdparts();
        const char *mtdids = get_mtdids();
        const char *mtdparts_next = mtdparts;
        struct mtd_info *mtd;

        mtd_probe_uclass_mtd_devs();

        /*
         * Check if mtdparts/mtdids changed, if the MTD dev list was updated
         * or if our previous attempt to delete existing partititions failed.
         * In any of these cases we want to update the partitions, otherwise,
         * everything is up-to-date and we can return 0 directly.
         */
        if ((!mtdparts && !old_mtdparts && !mtdids && !old_mtdids) ||
            (mtdparts && old_mtdparts && mtdids && old_mtdids &&
             !mtd_dev_list_updated() && !mtd_del_all_parts_failed &&
             !strcmp(mtdparts, old_mtdparts) &&
             !strcmp(mtdids, old_mtdids)))
                return 0;

        /* Update the local copy of mtdparts */
        free(old_mtdparts);
        free(old_mtdids);
        old_mtdparts = strdup(mtdparts);
        old_mtdids = strdup(mtdids);

        /*
         * Remove all old parts. Note that partition removal can fail in case
         * one of the partition is still being used by an MTD user, so this
         * does not guarantee that all old partitions are gone.
         */
        mtd_del_all_parts();

        /*
         * Call mtd_dev_list_updated() to clear updates generated by our own
         * parts removal loop.
         */
        mtd_dev_list_updated();

        /* If either mtdparts or mtdids is empty, then exit */
        if (!mtdparts || !mtdids)
                return 0;

        /* Start the parsing by ignoring the extra 'mtdparts=' prefix, if any */
        if (!strncmp(mtdparts, "mtdparts=", sizeof("mtdparts=") - 1))
                mtdparts += 9;

        /* For each MTD device in mtdparts */
        for (; mtdparts[0] != '\0'; mtdparts = mtdparts_next) {
                char mtd_name[MTD_NAME_MAX_LEN], *colon;
                struct mtd_partition *parts;
                unsigned int mtd_name_len;
                int nparts, ret;

                mtdparts_next = strchr(mtdparts, ';');
                if (!mtdparts_next)
                        mtdparts_next = mtdparts + strlen(mtdparts);
                else
                        mtdparts_next++;

                colon = strchr(mtdparts, ':');
                if (colon > mtdparts_next)
                        colon = NULL;

                if (!colon) {
                        printf("Wrong mtdparts: %s\n", mtdparts);
                        return -EINVAL;
                }

                mtd_name_len = (unsigned int)(colon - mtdparts);
                if (mtd_name_len + 1 > sizeof(mtd_name)) {
                        printf("MTD name too long: %s\n", mtdparts);
                        return -EINVAL;
                }

                strncpy(mtd_name, mtdparts, mtd_name_len);
                mtd_name[mtd_name_len] = '\0';
                /* Move the pointer forward (including the ':') */
                mtdparts += mtd_name_len + 1;
                mtd = get_mtd_device_nm(mtd_name);
                if (IS_ERR_OR_NULL(mtd)) {
                        char linux_name[MTD_NAME_MAX_LEN];

                        /*
                         * The MTD device named "mtd_name" does not exist. Try
                         * to find a correspondance with an MTD device having
                         * the same type and number as defined in the mtdids.
                         */
                        debug("No device named %s\n", mtd_name);
                        ret = mtd_search_alternate_name(mtd_name, linux_name,
                                                        MTD_NAME_MAX_LEN);
                        if (!ret)
                                mtd = get_mtd_device_nm(linux_name);

                        /*
                         * If no device could be found, move the mtdparts
                         * pointer forward until the next set of partitions.
                         */
                        if (ret || IS_ERR_OR_NULL(mtd)) {
                                printf("Could not find a valid device for %s\n",
                                       mtd_name);
                                mtdparts = mtdparts_next;
                                continue;
                        }
                }

                /*
                 * Call mtd_del_parts() again, even if it's already been called
                 * in mtd_del_all_parts(). We need to know if old partitions are
                 * still around (because they are still being used by someone),
                 * and if they are, we shouldn't create new partitions, so just
                 * skip this MTD device and try the next one.
                 */
                ret = mtd_del_parts(mtd, true);
                if (ret < 0)
                        continue;

                /*
                 * Parse the MTD device partitions. It will update the mtdparts
                 * pointer, create an array of parts (that must be freed), and
                 * return the number of partition structures in the array.
                 */
                ret = mtd_parse_partitions(mtd, &mtdparts, &parts, &nparts);
                if (ret) {
                        printf("Could not parse device %s\n", mtd->name);
                        put_mtd_device(mtd);
                        return -EINVAL;
                }

                if (!nparts)
                        continue;

                /* Create the new MTD partitions */
                add_mtd_partitions(mtd, parts, nparts);

                /* Free the structures allocated during the parsing */
                mtd_free_parsed_partitions(parts, nparts);

                put_mtd_device(mtd);
        }

        /*
         * Call mtd_dev_list_updated() to clear updates generated by our own
         * parts registration loop.
         */
        mtd_dev_list_updated();

        return 0;
}
#else
int mtd_probe_devices(void)
{
        mtd_probe_uclass_mtd_devs();

        return 0;
}
#endif /* defined(CONFIG_MTD_PARTITIONS) */