// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
 */

#include <common.h>
#include <dm.h>
#include <log.h>
#include <mmc.h>
#include <spl.h>
#include <asm/global_data.h>

#if CONFIG_IS_ENABLED(OF_LIBFDT)
/**
 * spl_node_to_boot_device() - maps from a DT-node to a SPL boot device
 * @node:       of_offset of the node
 *
 * The SPL framework uses BOOT_DEVICE_... constants to identify its boot
 * sources.  These may take on a device-specific meaning, depending on
 * what nodes are enabled in a DTS (e.g. BOOT_DEVICE_MMC1 may refer to
 * different controllers/block-devices, depending on which SD/MMC controllers
 * are enabled in any given DTS).  This function maps from a DT-node back
 * onto a BOOT_DEVICE_... constant, considering the currently active devices.
 *
 * Returns
 *   -ENOENT, if no device matching the node could be found
 *   -ENOSYS, if the device matching the node can not be mapped onto a
 *            SPL boot device (e.g. the third MMC device)
 *   -1, for unspecified failures
 *   a positive integer (from the BOOT_DEVICE_... family) on succes.
 */

static int spl_node_to_boot_device(int node)
{
        struct udevice *parent;

        /*
         * This should eventually move into the SPL code, once SPL becomes
         * aware of the block-device layer.  Until then (and to avoid unneeded
         * delays in getting this feature out), it lives at the board-level.
         */
        if (!uclass_get_device_by_of_offset(UCLASS_MMC, node, &parent)) {
                struct udevice *dev;
                struct blk_desc *desc = NULL;

                for (device_find_first_child(parent, &dev);
                     dev;
                     device_find_next_child(&dev)) {
                        if (device_get_uclass_id(dev) == UCLASS_BLK) {
                                desc = dev_get_uclass_plat(dev);
                                break;
                        }
                }

                if (!desc)
                        return -ENOENT;

                switch (desc->devnum) {
                case 0:
                        return BOOT_DEVICE_MMC1;
                case 1:
                        return BOOT_DEVICE_MMC2;
                default:
                        return -ENOSYS;
                }
        } else if (!uclass_get_device_by_of_offset(UCLASS_SPI_FLASH, node,
                &parent)) {
                return BOOT_DEVICE_SPI;
        }

        /*
         * SPL doesn't differentiate SPI flashes, so we keep the detection
         * brief and inaccurate... hopefully, the common SPL layer can be
         * extended with awareness of the BLK layer (and matching OF_CONTROL)
         * soon.
         */
        if (!uclass_get_device_by_of_offset(UCLASS_SPI_FLASH, node, &parent))
                return BOOT_DEVICE_SPI;

        return -1;
}

/**
 * board_spl_was_booted_from() - retrieves the of-path the SPL was loaded from
 *
 * To support a 'same-as-spl' specification in the search-order for the next
 * stage, we need a SoC- or board-specific way to handshake with what 'came
 * before us' (either a BROM or TPL stage) and map the info retrieved onto
 * a OF path.
 *
 * Returns
 *   NULL, on failure or if the device could not be identified
 *   a of_path (a string), on success
 */
__weak const char *board_spl_was_booted_from(void)
{
        debug("%s: no support for 'same-as-spl' for this board\n", __func__);
        return NULL;
}

void board_boot_order(u32 *spl_boot_list)
{
        /* In case of no fdt (or only plat), use spl_boot_device() */
        if (!CONFIG_IS_ENABLED(OF_CONTROL) || CONFIG_IS_ENABLED(OF_PLATDATA)) {
                spl_boot_list[0] = spl_boot_device();
                return;
        }

        const void *blob = gd->fdt_blob;
        int chosen_node = fdt_path_offset(blob, "/chosen");
        int idx = 0;
        int elem;
        int boot_device;
        int node;
        const char *conf;

        if (chosen_node < 0) {
                debug("%s: /chosen not found, using spl_boot_device()\n",
                      __func__);
                spl_boot_list[0] = spl_boot_device();
                return;
        }

        for (elem = 0;
             (conf = fdt_stringlist_get(blob, chosen_node,
                                        "u-boot,spl-boot-order", elem, NULL));
             elem++) {
                const char *alias;

                /* Handle the case of 'same device the SPL was loaded from' */
                if (strncmp(conf, "same-as-spl", 11) == 0) {
                        conf = board_spl_was_booted_from();
                        if (!conf)
                                continue;
                }

                /* First check if the list element is an alias */
                alias = fdt_get_alias(blob, conf);
                if (alias)
                        conf = alias;

                /* Try to resolve the config item (or alias) as a path */
                node = fdt_path_offset(blob, conf);
                if (node < 0) {
                        debug("%s: could not find %s in FDT\n", __func__, conf);
                        continue;
                }

                /* Try to map this back onto SPL boot devices */
                boot_device = spl_node_to_boot_device(node);
                if (boot_device < 0) {
                        debug("%s: could not map node @%x to a boot-device\n",
                              __func__, node);
                        continue;
                }

                spl_boot_list[idx++] = boot_device;
        }

        /* If we had no matches, fall back to spl_boot_device */
        if (idx == 0)
                spl_boot_list[0] = spl_boot_device();
}
#endif