// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 Google, Inc
 * Written by Simon Glass <sjg@chromium.org>
 */

#include <common.h>
#include <env.h>
#include <env_internal.h>
#include <log.h>
#include <asm/global_data.h>
#include <linux/bitops.h>
#include <linux/bug.h>

DECLARE_GLOBAL_DATA_PTR;

#if defined(CONFIG_NEEDS_MANUAL_RELOC)
void env_fix_drivers(void)
{
        struct env_driver *drv;
        const int n_ents = ll_entry_count(struct env_driver, env_driver);
        struct env_driver *entry;

        drv = ll_entry_start(struct env_driver, env_driver);
        for (entry = drv; entry != drv + n_ents; entry++) {
                if (entry->name)
                        entry->name += gd->reloc_off;
                if (entry->load)
                        entry->load += gd->reloc_off;
                if (entry->save)
                        entry->save += gd->reloc_off;
                if (entry->erase)
                        entry->erase += gd->reloc_off;
                if (entry->init)
                        entry->init += gd->reloc_off;
        }
}
#endif

static struct env_driver *_env_driver_lookup(enum env_location loc)
{
        struct env_driver *drv;
        const int n_ents = ll_entry_count(struct env_driver, env_driver);
        struct env_driver *entry;

        drv = ll_entry_start(struct env_driver, env_driver);
        for (entry = drv; entry != drv + n_ents; entry++) {
                if (loc == entry->location)
                        return entry;
        }

        /* Not found */
        return NULL;
}

static enum env_location env_locations[] = {
#ifdef CONFIG_ENV_IS_IN_EEPROM
        ENVL_EEPROM,
#endif
#ifdef CONFIG_ENV_IS_IN_EXT4
        ENVL_EXT4,
#endif
#ifdef CONFIG_ENV_IS_IN_FAT
        ENVL_FAT,
#endif
#ifdef CONFIG_ENV_IS_IN_FLASH
        ENVL_FLASH,
#endif
#ifdef CONFIG_ENV_IS_IN_MMC
        ENVL_MMC,
#endif
#ifdef CONFIG_ENV_IS_IN_NAND
        ENVL_NAND,
#endif
#ifdef CONFIG_ENV_IS_IN_NVRAM
        ENVL_NVRAM,
#endif
#ifdef CONFIG_ENV_IS_IN_REMOTE
        ENVL_REMOTE,
#endif
#ifdef CONFIG_ENV_IS_IN_SPI_FLASH
        ENVL_SPI_FLASH,
#endif
#ifdef CONFIG_ENV_IS_IN_UBI
        ENVL_UBI,
#endif
#ifdef CONFIG_ENV_IS_NOWHERE
        ENVL_NOWHERE,
#endif
};

static bool env_has_inited(enum env_location location)
{
        return gd->env_has_init & BIT(location);
}

static void env_set_inited(enum env_location location)
{
        /*
         * We're using a 32-bits bitmask stored in gd (env_has_init)
         * using the above enum value as the bit index. We need to
         * make sure that we're not overflowing it.
         */
        BUILD_BUG_ON(ENVL_COUNT > BITS_PER_LONG);

        gd->env_has_init |= BIT(location);
}

/**
 * arch_env_get_location() - Returns the best env location for an arch
 * @op: operations performed on the environment
 * @prio: priority between the multiple environments, 0 being the
 *        highest priority
 *
 * This will return the preferred environment for the given priority.
 * This is overridable by architectures if they need to and has lower
 * priority than board side env_get_location() override.
 *
 * All implementations are free to use the operation, the priority and
 * any other data relevant to their choice, but must take into account
 * the fact that the lowest prority (0) is the most important location
 * in the system. The following locations should be returned by order
 * of descending priorities, from the highest to the lowest priority.
 *
 * Returns:
 * an enum env_location value on success, a negative error code otherwise
 */
__weak enum env_location arch_env_get_location(enum env_operation op, int prio)
{
        if (prio >= ARRAY_SIZE(env_locations))
                return ENVL_UNKNOWN;

        return env_locations[prio];
}

/**
 * env_get_location() - Returns the best env location for a board
 * @op: operations performed on the environment
 * @prio: priority between the multiple environments, 0 being the
 *        highest priority
 *
 * This will return the preferred environment for the given priority.
 * This is overridable by boards if they need to.
 *
 * All implementations are free to use the operation, the priority and
 * any other data relevant to their choice, but must take into account
 * the fact that the lowest prority (0) is the most important location
 * in the system. The following locations should be returned by order
 * of descending priorities, from the highest to the lowest priority.
 *
 * Returns:
 * an enum env_location value on success, a negative error code otherwise
 */
__weak enum env_location env_get_location(enum env_operation op, int prio)
{
        return arch_env_get_location(op, prio);
}

/**
 * env_driver_lookup() - Finds the most suited environment location
 * @op: operations performed on the environment
 * @prio: priority between the multiple environments, 0 being the
 *        highest priority
 *
 * This will try to find the available environment with the highest
 * priority in the system.
 *
 * Returns:
 * NULL on error, a pointer to a struct env_driver otherwise
 */
static struct env_driver *env_driver_lookup(enum env_operation op, int prio)
{
        enum env_location loc = env_get_location(op, prio);
        struct env_driver *drv;

        if (loc == ENVL_UNKNOWN)
                return NULL;

        drv = _env_driver_lookup(loc);
        if (!drv) {
                debug("%s: No environment driver for location %d\n", __func__,
                      loc);
                return NULL;
        }

        return drv;
}

int env_load(void)
{
        struct env_driver *drv;
        int best_prio = -1;
        int prio;

        if (CONFIG_IS_ENABLED(ENV_WRITEABLE_LIST)) {
                /*
                 * When using a list of writeable variables, the baseline comes
                 * from the built-in default env. So load this first.
                 */
                env_set_default(NULL, 0);
        }

        for (prio = 0; (drv = env_driver_lookup(ENVOP_LOAD, prio)); prio++) {
                int ret;

                if (!env_has_inited(drv->location))
                        continue;

                printf("Loading Environment from %s... ", drv->name);
                /*
                 * In error case, the error message must be printed during
                 * drv->load() in some underlying API, and it must be exactly
                 * one message.
                 */
                ret = drv->load();
                if (!ret) {
                        printf("OK\n");
                        gd->env_load_prio = prio;

#if !CONFIG_IS_ENABLED(ENV_APPEND)
                        return 0;
#endif
                } else if (ret == -ENOMSG) {
                        /* Handle "bad CRC" case */
                        if (best_prio == -1)
                                best_prio = prio;
                } else {
                        debug("Failed (%d)\n", ret);
                }
        }

        /*
         * In case of invalid environment, we set the 'default' env location
         * to the best choice, i.e.:
         *   1. Environment location with bad CRC, if such location was found
         *   2. Otherwise use the location with highest priority
         *
         * This way, next calls to env_save() will restore the environment
         * at the right place.
         */
        if (best_prio >= 0)
                debug("Selecting environment with bad CRC\n");
        else
                best_prio = 0;

        gd->env_load_prio = best_prio;

        return -ENODEV;
}

int env_reload(void)
{
        struct env_driver *drv;

        drv = env_driver_lookup(ENVOP_LOAD, gd->env_load_prio);
        if (drv) {
                int ret;

                printf("Loading Environment from %s... ", drv->name);

                if (!env_has_inited(drv->location)) {
                        printf("not initialized\n");
                        return -ENODEV;
                }

                ret = drv->load();
                if (ret)
                        printf("Failed (%d)\n", ret);
                else
                        printf("OK\n");

                if (!ret)
                        return 0;
        }

        return -ENODEV;
}

int env_save(void)
{
        struct env_driver *drv;

        drv = env_driver_lookup(ENVOP_SAVE, gd->env_load_prio);
        if (drv) {
                int ret;

                printf("Saving Environment to %s... ", drv->name);
                if (!drv->save) {
                        printf("not possible\n");
                        return -ENODEV;
                }

                if (!env_has_inited(drv->location)) {
                        printf("not initialized\n");
                        return -ENODEV;
                }

                ret = drv->save();
                if (ret)
                        printf("Failed (%d)\n", ret);
                else
                        printf("OK\n");

                if (!ret)
                        return 0;
        }

        return -ENODEV;
}

int env_erase(void)
{
        struct env_driver *drv;

        drv = env_driver_lookup(ENVOP_ERASE, gd->env_load_prio);
        if (drv) {
                int ret;

                if (!drv->erase) {
                        printf("not possible\n");
                        return -ENODEV;
                }

                if (!env_has_inited(drv->location)) {
                        printf("not initialized\n");
                        return -ENODEV;
                }

                printf("Erasing Environment on %s... ", drv->name);
                ret = drv->erase();
                if (ret)
                        printf("Failed (%d)\n", ret);
                else
                        printf("OK\n");

                if (!ret)
                        return 0;
        }

        return -ENODEV;
}

int env_init(void)
{
        struct env_driver *drv;
        int ret = -ENOENT;
        int prio;

        for (prio = 0; (drv = env_driver_lookup(ENVOP_INIT, prio)); prio++) {
                if (!drv->init || !(ret = drv->init()))
                        env_set_inited(drv->location);
                if (ret == -ENOENT)
                        env_set_inited(drv->location);

                debug("%s: Environment %s init done (ret=%d)\n", __func__,
                      drv->name, ret);

                if (gd->env_valid == ENV_INVALID)
                        ret = -ENOENT;
        }

        if (!prio)
                return -ENODEV;

        if (ret == -ENOENT) {
                gd->env_addr = (ulong)&default_environment[0];
                gd->env_valid = ENV_VALID;

                return 0;
        }

        return ret;
}

int env_select(const char *name)
{
        struct env_driver *drv;
        const int n_ents = ll_entry_count(struct env_driver, env_driver);
        struct env_driver *entry;
        int prio;
        bool found = false;

        printf("Select Environment on %s: ", name);

        /* search ENV driver by name */
        drv = ll_entry_start(struct env_driver, env_driver);
        for (entry = drv; entry != drv + n_ents; entry++) {
                if (!strcmp(entry->name, name)) {
                        found = true;
                        break;
                }
        }

        if (!found) {
                printf("driver not found\n");
                return -ENODEV;
        }

        /* search priority by driver */
        for (prio = 0; (drv = env_driver_lookup(ENVOP_INIT, prio)); prio++) {
                if (entry->location == env_get_location(ENVOP_LOAD, prio)) {
                        /* when priority change, reset the ENV flags */
                        if (gd->env_load_prio != prio) {
                                gd->env_load_prio = prio;
                                gd->env_valid = ENV_INVALID;
                                gd->flags &= ~GD_FLG_ENV_DEFAULT;
                        }
                        printf("OK\n");
                        return 0;
                }
        }
        printf("priority not found\n");

        return -ENODEV;
}